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Selling General And Administrative Expenses [Abstract]

Cost of revenue

21. Cost of revenue

Cost of revenue consists of the following:

	Year ended December 31,
	2015		2016		2017
Personnel expenses	$	1,013,209	$	1,061,501	$	1,155,745
Operational expenses		432,535		446,922		481,012
Depreciation and amortization		47,803		46,284		46,947
	$	1,493,547	$	1,554,707	$	1,683,704

Selling, general and administrative expenses

12 Months Ended

Dec. 31, 2017

Selling, general and administrative expenses

22. Selling, general and administrative expenses

Selling, general and administrative expenses consist of the following:

	Year ended December 31,
	2015		2016		2017
Personnel expenses	$	430,088	$	469,956	$	501,445
Operational expenses		169,042		174,060		178,573
Depreciation and amortization		8,984		9,013		9,829
	$	608,114	$	653,029	$	689,847

Other operating (income) expense, net

12 Months Ended

Dec. 31, 2017

Other operating (income) expense, net

23. Other operating (income) expense, net

	Year ended December 31,
	2015			2016			2017
Other operating (income) expense	$	(2,515	)	$	(1,266	)	$	(7,277	)
Provision for impairment of intangible assets and property, plant and equipment		10,714			11,195			9,311
Change in fair value of earn-out consideration and deferred consideration (relating to business acquisitions)		(11,521	)		(14,869	)		(3,695	)
Other operating (income) expense, net	$	(3,322	)	$	(4,940	)	$	(1,661	)

Interest income (expense), net

12 Months Ended

Dec. 31, 2017

Banking And Thrift Interest [Abstract]

Interest income (expense), net

24. Interest income (expense), net

Interest income (expense), net consists of the following:

	Year ended December 31,
	2015			2016			2017
Interest income	$	8,676		$	7,247		$	8,182
Interest expense		(29,828	)		(23,431	)		(39,917	)
Loss on extinguishment of debt		(10,115	)		-			-
Interest income (expense), net	$	(31,267	)	$	(16,184	)	$	(31,735	)

Income taxes

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Income taxes

25. Income taxes

Income tax expense (benefit) for the years ended December 31, 2015, 2016 and 2017 is allocated as follows:

	Year ended December 31,
	2015			2016			2017

Income from continuing operations	$	61,937		$	62,098		$	59,742
Other comprehensive Income:
Unrealized gains (losses) on cash flow hedges		13,816			23,809			457
Retirement benefits		1,304			(1,885	)		670
Additional paid in capital:
Excess tax benefit on stock-based compensation		(6,560	)		—			—
Retained earnings:
Deferred tax assets recognized on early adoption of ASU 2016-09		—			(24,912	)		—

The components of income before income tax expense from continuing operations are as follows:

	Year ended December 31,
	2015		2016		2017
Domestic (U.S.)	$	23,122	$	44,110	$	8,440
Foreign (Non-U.S.)		278,632		285,535		312,143
Income before income taxes	$	301,754	$	329,645	$	320,583

25. Income taxes (Continued)

Income tax expense (benefit) attributable to income from continuing operations consists of:

	Year ended December 31,
	2015			2016			2017
Current taxes:
Domestic (U.S. federal taxes)	$	12,142		$	78		$	3,380
Domestic (U.S. state taxes)		301			1,069			1,268
Foreign (Non-U.S.)		68,207			30,497			65,485
	$	80,650		$	31,644		$	70,133
Deferred taxes:
Domestic (U.S. federal taxes)	$	(5,396	)	$	11,379		$	3,549
Domestic (U.S. state taxes)		344			(459	)		(2,809	)
Foreign (Non-U.S.)		(13,661	)		19,534			(11,131	)
	$	(18,713	)	$	30,454		$	(10,391	)
Total income tax expense (benefit)	$	61,937		$	62,098		$	59,742

Income tax expense (benefit) attributable to income from continuing operations differed from the amounts computed by applying the U.S. federal statutory income tax rate of 35% to income before income taxes, as a result of the following:

	Year ended December 31,
	2015			2016			2017
Income before income tax expense	$	301,754		$	329,645		$	320,583
Statutory tax rates		35	%		35	%		35	%
Computed expected income tax expense		105,614			115,376			112,204
Increase (decrease) in income taxes resulting from:
Foreign tax rate differential		(16,550	)		(18,574	)		(25,224	)
Tax benefit from tax holiday		(38,039	)		(32,893	)		(35,814	)
Non-deductible expenses		1,884			2,295			1,146
Effect of change in tax rates		1,436			353			2,778
Change in valuation allowance		(33	)		(4,830	)		9,041
Unrecognized tax benefits		6,272			(627	)		1,611
Other*		1,353			998			(6,000	)
Reported income tax expense (benefit)	$	61,937		$	62,098		$	59,742
*During 2017, following the transfer/closure of certain affiliated entities, deferred tax liabilities recorded against the outside basis difference amounting to $9,600 were reversed. It was not more likely than not that the resulting net deferred tax asset would be realized. Therefore, a full valuation allowance was established to offset the reduction in deferred tax liabilities.

A portion of the profits of the Company’s operations is exempt from income tax in India. One of the Company’s Indian subsidiaries has sixteen units eligible for a tax holiday as a special economic zone unit in respect of 100% of the export profits it generates for a period of 5 years from commencement, 50% of such profits for the next 5 years (year 6 to year 10 from commencement) and 50% of the profits for an additional period of 5 years (year 11 to year 15 from commencement), subject to the satisfaction of certain capital investment requirements. The tax holidays for the Company’s existing special economic zone units will begin to expire on March 31, 2022 and will have fully expired on March 31, 2029, assuming the Company satisfies the capital investment requirements.

The effect of the Indian tax holiday on basic earnings per share was $0.18, $0.19 and $0.18, respectively, for the years ended December 31, 2015, 2016 and 2017. The effect of the tax holiday on diluted earnings per share was $0.17, $0.18 and $0.18, respectively, for the years ended December 31, 2015, 2016 and 2017.

25. Income taxes (Continued)

The components of the Company’s deferred tax balances as of December 31, 2016 and 2017 are as follows:

	As of December 31,
	2016			2017
Deferred tax assets
Net operating loss carryforwards	$	52,997		$	55,500
Accrued liabilities and other expenses		19,840			41,177
Provision for doubtful debts		6,419			10,509
Property, plant and equipment		3,445			1,270
Unrealized losses on cash flow hedges, Net		558			275
Share-based compensation		19,054			19,789
Retirement benefits		5,067			5,817
Deferred revenue		44,892			22,948
Tax credit carryforwards		34,509			35,322
Other		8,876			11,571
Gross deferred tax assets	$	195,657		$	204,178
Less: valuation allowance		(14,746	)		(24,549	)
Total deferred tax assets	$	180,911		$	179,629
Deferred tax liabilities
Intangible assets	$	13,519		$	15,954
Property, plant and equipment		2,745			1,131
Deferred cost		41,950			33,816
Investments in foreign subsidiaries not indefinitely reinvested		29,546			18,949
Unrealized gains on cash flow hedges, net		14,350			14,711
Other		11,073			24,886
Total deferred tax liabilities	$	113,183		$	109,447
Net deferred tax asset	$	67,728		$	70,182

	As of December 31,
Classified as	2016		2017
Deferred tax assets
Non-current	$	70,143	$	76,929
Deferred tax liabilities
Non-current		2,415		6,747
	$	67,728	$	70,182

The change in the total valuation allowance for deferred tax assets as of December 31, 2015, 2016 and 2017 is as follows:

	Year ended December 31,
	2015			2016			2017
Opening valuation allowance	$	21,094		$	20,091		$	14,746
Reduction during the year		(3,499	)		(7,299	)		(3,957	)
Addition during the year		2,496			1,954			13,760
Closing valuation allowance	$	20,091		$	14,746		$	24,549

25. Income taxes (Continued)

In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets depends on the generation of future taxable income during the periods in which temporary differences are deductible.

Management considers the scheduled reversal of deferred tax liabilities and projected taxable income in making this assessment. In order to fully realize a deferred tax asset, the Company must generate future taxable income prior to the expiration of the deferred tax asset under applicable law. Based on the level of historical taxable income and projections for future taxable income over the periods during which the Company’s deferred tax assets are deductible, management believes that it is more likely than not that the Company will realize the benefits of these deductible differences, net of the existing valuation allowances as of December 31, 2017. The amount of the Company’s deferred tax assets considered realizable, however, could be reduced in the near term if estimates of future taxable income during the carryforward period are reduced.

In 2016, one of the Company’s subsidiaries filed amended tax returns with respect to prior years, resulting in revised assessments, higher taxable income and the utilization of operating loss carryforwards. The use of operating loss carryforwards resulted in the complete reversal of the subsidiary’s remaining valuation allowance of $3,377.

On January 1, 2016, the Company elected the early adoption of ASU 2016-09, which was applied using a modified retrospective approach. Accordingly, excess tax benefits relating to the exercise of stock options prior to December 31, 2015 amounting to $24,912 were recorded through retained earnings. For the year ended December 31, 2016 and 2017, the Company has recognized net excess tax benefits of $1,004 and $1,723 in income tax expense attributable to continuing operations.

The Company recorded excess tax benefits of $6,560, $0, and $0 through additional paid-in capital during the years ended December 31, 2015, 2016 and 2017, respectively.

As of December 31, 2017, the Company’s deferred tax assets related to net operating loss carryforwards of $223,415 amounted to $50,495 (excluding state net operating losses). Net operating losses of subsidiaries in the United Kingdom, Singapore, Malaysia, Australia, Brazil, Israel, South Africa, Hong Kong and Luxembourg amounted to $126,612 and can be carried forward for an indefinite period.

25. Income taxes (Continued)

The Company’s remaining tax loss carryforwards expire as set forth in the table below:

	US – Federal		Europe		Others
Year ending December 31,
2018	$	—	$	—	$	20
2019		—		—		72
2020		—		1,872		62
2021		—		581		2,084
2022		—		5,253		60
2023		—		8,500		953
2024		—		1,213		7,941
2025		—		28,222		9,647
2026		9,511		2,263		3,072
2027		9,913		—		2,053
2028		—		33		2,451
2034		—		—		1,027
	$	19,424	$	47,937	$	29,442

In the table above, “Europe” includes net operating losses of subsidiaries in Hungary, Poland, the Netherlands, the Czech Republic, Slovakia, and Portugal, while “Others” includes net operating losses of subsidiaries in Mexico, Japan, China, India and Canada.

As of December 31, 2017, the Company had additional deferred tax assets for U.S. state and local tax loss carryforwards amounting to $5,005 with varying expiration periods between 2018 and 2036.

As of December 31, 2017, the company had a total foreign tax credit carryforward of $33,220, which will expire as set forth in the table below:

Year ending December 31,	Amount
2023	$	893
2024		1,202
2025		15,552
2026		8,481
2027		5,362
2028		1,730
	$	33,220

Undistributed earnings of the Company’s foreign (non-Bermuda) subsidiaries which cannot be repatriated in a tax-free manner and for which a deferred tax liability has not been recognized amounted to $36,029 as of December 31, 2017. The Company has not accrued any income, distribution or withholding taxes that would arise if such earnings were repatriated. Due to the Company’s changing corporate structure, the various methods that are available to repatriate earnings, and uncertainty relative to the applicable taxes at the time of repatriation, it is not practicable to determine the amount of tax that would be imposed upon repatriation. If undistributed earnings are repatriated in the future, or are no longer deemed to be indefinitely reinvested, the company will accrue the applicable amount of taxes associated with such earnings at that time.

25. Income taxes (Continued)

As of December 31, 2017, $499,532 of the Company’s $504,468, in cash and cash equivalents was held by the Company’s foreign (non-Bermuda) subsidiaries. $243,813 of this cash is held by foreign subsidiaries for which the Company expects to incur and has accrued a deferred tax liability on the repatriation of $17,343 of retained earnings. $122,674 of the Company’s cash and cash equivalents is held by foreign subsidiaries in jurisdictions where no tax is expected to be imposed upon repatriation. The remaining $133,045 in cash and cash equivalents held by certain foreign subsidiaries of the Company is being indefinitely reinvested.

On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cut and Jobs Act (the “Tax Act”). The Tax Act makes broad and complex changes to the U.S. tax code that affect 2017. The Tax Act also establishes new tax laws that will affect 2018 and subsequent years, including a reduction in the U.S. federal corporate income tax rate from 35% to 21%.

On December 22, 2017, the SEC staff issued Staff Accounting Bulletin No. 118 (“SAB 118”), which provides guidance on accounting for the tax effects of the Tax Act. SAB 118 provides a measurement period that should not extend beyond one year from the Tax Act enactment date for companies to complete the accounting under ASC 740, Income Taxes. In accordance with SAB 118, a company must reflect the income tax effects of those aspects of the Tax Act for which the accounting under ASC 740 is complete. To the extent that a company’s accounting for certain income tax effects of the Tax Act is incomplete but it is able to determine a reasonable estimate, it must record a provisional estimate in the financial statements.

As a result of the reduction in the federal corporate income tax rate, the Company has revalued its net deferred tax assets, excluding tax credits to the extent affected by changes in the law as of December 31, 2017. Based on this revaluation, the Company has recorded a net tax expense of $3,182 to reduce its net deferred tax asset balance, which was recorded as additional income tax expense for the year ended December 31, 2017. Additionally, the Company has claimed 100% depreciation on $7,685 of the investments it made in depreciable property after September 27, 2017.

The estimation of transition tax on mandatory repatriation introduced under the Tax Act is provisional, which is currently estimated based on information available as of December 31, 2017. The Company has not recorded any tax liability for transition tax as of December 31, 2017 pending detailed workings for the earnings and profit pool of its controlled foreign corporations. The Company will recognize any changes to the provisional amounts as it refines its estimates and interpretations of the application of the Tax Act. The Company expects to complete its analysis of the provisional items during the second half of 2018. The effects of other provisions of the Tax Act are not expected to have a material impact on the Company’s consolidated financial statements for the year ended December 31, 2017.

25. Income taxes (Continued)

The following table summarizes activities related to our unrecognized tax benefits from January 1 to December 31 for each of 2015, 2016 and 2017:

	Year Ended December 31,
	2015			2016			2017
Opening balance at January 1	$	22,718		$	26,357		$	23,467
Increase related to prior year tax positions, including recorded in acquisition accounting		2,000			370			2,582
Decrease related to prior year tax positions		—			(1,506	)		(1,398	)
Decrease related to divestiture of business		—			(345	)		—
Decrease related to prior year tax position due to lapse of applicable statute of limitation		(820	)		(2,122	)		(1,019	)
Increase related to current year tax positions, including recorded in acquisition accounting		3,544			3,225			1,661
Decrease related to settlements with tax Authorities		—			(2,000	)		—
Effect of exchange rate changes		(1,085	)		(512	)		767
Closing balance at December 31	$	26,357		$	23,467		$	26,060

As of December 31, 2015, 2016 and 2017, the Company had unrecognized tax benefits amounting to $24,935, $22,469 and $24,877, respectively, which, if recognized, would impact the effective tax rate.

As of December 31, 2015, 2016 and 2017, the Company had accrued $4,223, $3,856 and $4,614, respectively, in interest relating to unrecognized tax benefits. During the years ended December 31, 2015, 2016 and 2017, the Company recognized $1,152, $(206) and $(224), respectively, excluding exchange rate differences, in interest on unrecognized tax benefits. As of December 31, 2015, 2016 and 2017, the company had accrued $958, $977 and $1,033, respectively, for penalties.

In the next twelve months and for all tax years that remain open to examinations by U.S. federal and various state, local, and non-U.S. tax authorities, the Company estimates that it is reasonably possible that the total amount of its unrecognized tax benefits will vary. However, the Company does not expect significant changes within the next twelve months other than depending on the progress of tax matters or examinations with various tax authorities, which are difficult to predict.

With exceptions, the Company is no longer subject to U.S. federal, state and local or non-U.S. income tax audits by taxing authorities for years prior to 2013. The Company’s subsidiaries in India and China are open to examination by relevant taxing authorities for tax years beginning on or after April 1, 2009, and January 1, 2007, respectively. The Company regularly reviews the likelihood of additional tax assessments and adjusts its reserves as additional information or events require.

Segment reporting

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Segment reporting

26. Segment reporting

The Company manages various types of business process and information technology services in an integrated manner for clients in various industries and geographic locations. The Company’s Chief Executive Officer, who has been identified as the Chief Operation Decision Maker (CODM), reviews financial information prepared on a consolidated basis, accompanied by disaggregated information about revenue and adjusted operating income by identified business units. The identified business units are organized for operational reasons and represent either services-based, customer-based, industry-based or geography-based units. There is significant overlap between the manner in which the business units are organized. Additionally, the composition and organization of the business units is fluid and the structure changes regularly in response to growth of the overall business, acquisitions and changes in the reporting structure, clients, services, industries served, and delivery centers.

Based on an overall evaluation of all facts and circumstances, and after combining operating segments with similar economic characteristics that comply with other aggregation criteria specified in the FASB guidance on segment reporting, the Company has determined that it operates as a single reportable segment.

Net revenues by service type are as follows:

	Year ended December 31,
	2015		2016		2017
Business process outsourcing	$	1,933,095	$	2,083,450	$	2,264,335
Information technology services		527,949		487,306		472,594
Total net revenues	$	2,461,044	$	2,570,756	$	2,736,929

Revenues from clients based on the industry serviced are as follows:

	Year ended December 31,
	2015		2016		2017
Banking, financial services and insurance	$	1,030,584	$	1,055,704	$	1,105,731
Manufacturing, including pharmaceuticals and medical equipment manufacturing		878,570		958,779		1,002,973
Technology, healthcare and other services		551,890		556,273		628,225
Total net revenues	$	2,461,044	$	2,570,756	$	2,736,929

Net revenues from geographic areas based on the location of the Company’s service delivery centers are as follows. A portion of net revenues attributable to India consists of net revenues for services performed by delivery centers in India or at clients’ premises outside of India by business units or personnel normally based in India.

	Year ended December 31,
	2015		2016		2017
India	$	1,687,699	$	1,804,113	$	1,712,783
Asia, other than India		238,529		249,839		286,338
North and Latin America		304,879		282,434		455,059
Europe		229,937		234,370		282,749
Total net revenues	$	2,461,044	$	2,570,756	$	2,736,929

Revenues from GE comprised 19%, 14% and 10% of the Company’s consolidated total net revenues in 2015, 2016 and 2017, respectively. No other customer accounted for 10% or more of the Company’s consolidated total net revenues during these periods.

26. Segment reporting (Continued)

Property, plant and equipment, net by geographic region are as follows:

	As of December 31,
	2016		2017
India	$	116,417	$	125,490
Asia, other than India		13,549		15,899
North and Latin America		44,633		38,438
Europe		18,619		27,203
Total	$	193,218	$	207,030

Related party transactions	12 Months Ended
Related party transactions	Dec. 31, 2017
Related Party Transactions [Abstract]
Related party transactions	27. Related party transactions The Company has entered into related party transactions with its non-consolidating affiliates. The Company has also entered into related party transactions with a significant shareholder and its affiliates. The Company’s related party transactions can be categorized as follows: Revenue from services In the years ended December 31, 2015, 2016, and 2017, the Company recognized net revenues of $326, $335 and $398, respectively, from a client that is also a significant shareholder of the Company. In the years ended December 31, 2015, 2016 and 2017, the Company recognized net revenues of $7,826, $8,077 and $5,400, respectively, from a client that was a non-consolidating affiliate of the Company. As of June 30, 2017 this non-consolidating affiliate ceased to be a related party. Cost of revenue from services The Company purchases certain services from its non-consolidating affiliates, mainly relating to training and recruitment, the costs of which are included in cost of revenue. For the years ended December 31, 2015, 2016 and 2017, cost of revenue includes an amount of $2,173, $2,067 and $2,043, respectively, attributable to the cost of such services provided by the Company’s non-consolidating affiliates. Selling, general and administrative expenses The Company purchases certain services from its non-consolidating affiliates, mainly relating to training and recruitment, the costs of which are included in selling, general and administrative expenses. For the years ended December 31, 2015, 2016 and 2017, selling, general and administrative expenses include an amount of $384, $291 and $315, respectively, attributable to the cost of such services provided by the Company’s non-consolidating affiliates. During the years ended December 31, 2015, 2016 and 2017, the Company engaged a significant shareholder of the Company to provide services to the Company at a cost of $421, $58 and $57, respectively. Investment in equity affiliates During the years ended December 31, 2016 and 2017, the Company made investments of $5,884 and $496, respectively, in its non-consolidating affiliates. During the year ended December 31, 2017, the Company recorded a charge of $ 2,849 related to an investment in one of its non-consolidating affiliates. This charge has been included in equity-method investment activity, net in the Company’s consolidated statement of income. 27. Related party transactions (Continued) As of December 31, 2016 and 2017, the Company’s investments in its non-consolidating affiliates amounted to $4,800 and $886, respectively. Others During the years ended December 31, 2015, 2016 and 2017, the Company entered into transactions with one of its non-consolidating affiliates for certain cost reimbursements amounting to $2,077, $1,162 and $477, respectively. During the year ended December 31, 2017, the Company entered into transactions with a client that is a significant shareholder of the Company for certain cost reimbursements amounting to $127, of which $127 is receivable as of December 31, 2017. During the year ended December 31, 2016, the Company claimed a portion of an equity affiliate’s net operating losses under consortium relief in the United Kingdom amounting to $3,291, which was outstanding and had been included in other liabilities in the company’s consolidated balance sheet as of December 31, 2016. During the year ended December 31, 2017, the Company made a payment of $3,847 to one of its non-consolidating affiliates under a tax-sharing arrangement in the U.K. This amount represents a portion of the non-consolidated affiliate’s net operating losses surrendered to the Company under the tax sharing arrangement for the years 2015 and 2016. As of June 30, 2017 this non-consolidating affiliate ceased to be a related party.

Commitments and contingencies	12 Months Ended
Commitments and contingencies	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and contingencies	28. Commitments and contingencies Capital commitments As of December 31, 2016 and 2017, the Company has committed to spend $5,185 and $8,314, respectively, under agreements to purchase property, plant and equipment. This amount is net of capital advances paid in respect of such purchases. Bank guarantees The Company has outstanding bank guarantees amounting to $11,958 and $8,879 as of December 31, 2016 and 2017, respectively. Bank guarantees are generally provided to government agencies and excise and customs authorities for the purposes of maintaining a bonded warehouse. These guarantees may be revoked by the government agencies if they suffer any losses or damages through the breach of any of the covenants contained in the agreements governing such guarantees. Other commitments The Company’s business process delivery centers in India are 100% export-oriented units or Software Technology Parks of India (“STPI”) units under the STPI guidelines issued by the Government of India. These units are exempt from customs, central excise duties, and levies on imported and indigenous capital goods, stores, and spares. The Company has undertaken to pay custom duties, service taxes, levies, and liquidated damages payable, if any, in respect of imported and indigenous capital goods, stores, and spares consumed duty free, in the event that certain terms and conditions are not fulfilled.

Quarterly financial data (unaudited)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Quarterly financial data (unaudited)

29. Quarterly financial data (unaudited)

	Three months ended									Year ended
	March 31, 2017		June 30, 2017			September 30, 2017		December 31, 2017		December 31, 2017
Total net revenues	$	622,995	$	670,697		$	708,824	$	734,413	$	2,736,929
Gross profit	$	239,658	$	255,404		$	279,633	$	278,530	$	1,053,225
Income from operations	$	79,096	$	80,031		$	97,451	$	72,049	$	328,627
Income before equity method investment activity, net and income tax expense	$	69,243	$	84,582		$	89,742	$	81,559	$	325,126
Net Income	$	52,440	$	69,102		$	73,161	$	66,138	$	260,841
Net (income) loss attributable to redeemable non-controlling interest	$	898	$	(156	)	$	584	$	944	$	2,270
Net income attributable to Genpact Limited common shareholders	$	53,338	$	68,946		$	73,745	$	67,082	$	263,111
Earnings per common share attributable to Genpact Limited common shareholders
Basic	$	0.27	$	0.36		$	0.38	$	0.35	$	1.36
Diluted	$	0.26	$	0.36		$	0.38	$	0.34	$	1.34
Weighted average number of common shares used in computing earnings per common share attributable to Genpact Limited common shareholders
Basic		199,069,528		191,469,593			192,124,366		192,795,534		193,864,755
Diluted		202,655,937		193,732,406			194,947,699		196,862,168		197,049,552

29. Quarterly financial data (unaudited) (Continued)

	Three months ended								Year ended
	March 31, 2016		June 30, 2016		September 30, 2016		December 31, 2016		December 31, 2016
Total net revenues	$	609,703	$	630,523	$	648,783	$	681,747	$	2,570,756
Gross profit	$	236,855	$	246,768	$	256,351	$	276,075	$	1,016,049
Income from operations	$	75,622	$	79,940	$	87,124	$	98,092	$	340,777
Income before equity method investment activity, net and income tax expense	$	72,664	$	81,818	$	87,360	$	95,502	$	337,343
Net income	$	58,505	$	64,788	$	68,188	$	76,066	$	267,547
Net (income) loss attributable to redeemable non-controlling interest	$	289	$	882	$	734	$	232	$	2,137
Net income attributable to Genpact Limited common shareholders	$	58,794	$	65,670	$	68,922	$	76,298	$	269,684
Earnings per common share attributable to Genpact Limited common shareholders
Basic	$	0.28	$	0.31	$	0.33	$	0.38	$	1.30
Diluted	$	0.27	$	0.31	$	0.33	$	0.38	$	1.28
Weighted average number of common shares used in computing earnings per common share attributable to Genpact Limited common shareholders
Basic		210,780,165		210,178,050		206,146,007		200,341,922		206,861,536
Diluted		213,892,964		213,803,134		209,376,683		203,431,310		210,126,023

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	30. Subsequent Events Share Repurchase Pursuant to its share repurchase program, the Company repurchased 757,526 of its common shares between January 1, 2018 and March 1, 2018 on the open market at a weighted average price of $31.67 per share for an aggregate cash amount of $23,993. The Company repurchased 163,975 of its common shares at a weighted average price of $28.20 per share on January 17, 2018 upon final settlement of the transaction under the Company’s ASR agreement. The Company repurchased 7,092,928 of its common shares in the aggregate under the ASR agreement for an aggregate purchase price of $200,000. Dividend On February 12, 2018, the Company announced that its Board of Directors has approved a 25% increase in its quarterly cash dividend, representing a planned annual dividend of $0.30 per common share, increased from $0.24 per common share in 2017. The Board of Directors also declared a dividend for the first quarter of 2018 of $0.075 per common share, which will be paid on or about March 21, 2018 to shareholders of record as of the close of business on March 9, 2018. The declaration of any future dividends will be at the discretion of the Board of Directors.

Summary of significant accounting policies (Policies)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Basis of preparation and principles of consolidation

(a) Basis of preparation and principles of consolidation

Use of estimates

(b) Use of estimates

2. Summary of significant accounting policies (Continued)

Revenue recognition

Accounts receivable

2. Summary of significant accounting policies (Continued)

(d) Accounts receivable

Cash and cash equivalents

(e) Cash and cash equivalents

Cash and cash equivalents consist of cash and bank balances and all highly liquid investments purchased with an original maturity of three months or less.

Short- term investments

(f) Short-term investments

Property, plant and equipment, net

(g) Property, plant and equipment, net

		Years
Buildings		40
Furniture and fixtures		4
Computer equipment and servers		4
Plant, machinery and equipment		4
Computer software		4-7
Leasehold improvements		Lesser of lease period or 10 Years
Vehicles		3-4

2. Summary of significant accounting policies (Continued)

Business combinations

(h) Business combinations, goodwill and other intangible assets

Goodwill

Other Intangible Assets

Customer-related intangible assets		1-14 years
Marketing-related intangible assets		1-10 years
Technology-related intangible assets		2-8 years
Other intangible assets		3-5 years

2. Summary of significant accounting policies (Continued)

Impairment of long-lived assets

(i) Impairment of long-lived assets

Foreign currency

(j) Foreign currency

Derivative instruments and hedging activities

2. Summary of significant accounting policies (Continued)

(k) Derivative instruments and hedging activities

Income taxes

(l) Income taxes

2. Summary of significant accounting policies (Continued)

Employee benefit plans

(m) Employee benefit plans

Stock-based compensation

(n) Stock-based compensation

Accelerated Share Repurchase

(o) Accelerated Share Repurchase

Government incentives

2. Summary of significant accounting policies (Continued)

(p) Government incentives

Financial instruments and concentration of credit risk

(q) Financial instruments and concentration of credit risk

Earnings (loss) per share

(r) Earnings (loss) per share

Commitments and contingencies

(s) Commitments and contingencies

Recently issued accounting pronouncements

(t) Recently issued accounting pronouncements

The authoritative bodies release standards and guidance which are assessed by management for impact on the company’s consolidated financial statements.

The following recently released accounting standard has been adopted by the Company:

2. Summary of significant accounting policies (Continued)

The following recently released accounting standards have not yet been adopted by the Company:

2. Summary of significant accounting policies (Continued)

Reclassification

(v) Reclassification

Summary of significant accounting policies (Tables)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Schedule of Estimated Economic Useful Lives of Property Plant and Equipment

The Company depreciates and amortizes all property, plant and equipment using the straight-line method over the following estimated economic useful lives of the assets:

		Years
Buildings		40
Furniture and fixtures		4
Computer equipment and servers		4
Plant, machinery and equipment		4
Computer software		4-7
Leasehold improvements		Lesser of lease period or 10 Years
Vehicles		3-4

Estimated Useful Lives of Intangible Assets Acquired/Developed

Customer-related intangible assets		1-14 years
Marketing-related intangible assets		1-10 years
Technology-related intangible assets		2-8 years
Other intangible assets		3-5 years

Business acquisitions (Tables)

12 Months Ended

Dec. 31, 2017

Atyati Technologies Private Limited

Summary of Calculation of Gain (Loss) on Sale of Business

3. Business acquisitions (Continued)

The Company recorded a gain of $5,214 in its consolidated statement of income in connection with the sale of Atyati, calculated as follows:

Net sale proceeds	$	17,155
Net assets of the business, including intangible assets, allocated goodwill and the translation impact thereof		11,941
Gain on divestiture included in other income (expense), net	$	5,214

Europe | IT Support Business

Summary of Calculation of Gain (Loss) on Sale of Business

The Company recorded a loss of $5,668 in its consolidated statement of income in connection with the sale of the Business, calculated as follows:

Net sale proceeds	$	—
Net assets of the business, including the translation impact thereof		5,569
Selling expenses		99
Loss on divestiture included in other income (expense), net	$	5,668

Other Acquisitions

Summary of Acquisition Date, Goodwill Reporting Unit and Tax Deductibility of Goodwill of Each Acquisition

The following table sets forth, with respect to each of the five acquisitions, the acquisition date, goodwill reporting unit and the tax deductibility of the goodwill:


Acquisition	Acquisition date	Goodwill reporting unit	Tax deductibility of goodwill
U.S. Delivery Center	October 16, 2017	India	Deductible
OnSource	July 18, 2017	India	Deductible
Birlasoft	July 18, 2017	IT Services	Deductible
Fiserv	May 11, 2017	India	Non-deductible
Lease Dimensions	February 15, 2017	Americas	Non-deductible

- Definition

Tabular disclosure of information related to a disposal group. Includes, but is not limited to, a discontinued operation, disposal classified as held-for-sale or disposed of by means other than sale or disposal of an individually significant component.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=65878427&loc=SL51721533-107759

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 4B
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721665-107760

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64827811&loc=d3e1474-107760

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=64827811&loc=d3e1361-107760

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721683-107760

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3A
-URI http://asc.fasb.org/extlink&oid=84176398&loc=SL51724579-110230

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5C
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721675-107760

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 4A
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721663-107760

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84176398&loc=d3e2941-110230

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5B
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721673-107760

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 3A
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721659-107760

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5A
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721671-107760

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5D
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721677-107760

+ Details

Cash and cash equivalents (Tables)

12 Months Ended

Dec. 31, 2017

Cash And Cash Equivalents [Abstract]

Cash And Cash Equivalents

	As of December 31,
	2016		2017
Cash and other bank balances	$	422,623	$	504,468
Total	$	422,623	$	504,468

Accounts receivable, net of reserve for doubtful receivables (Tables)

12 Months Ended

Dec. 31, 2017

Receivables [Abstract]

Reserve for Doubtful Receivables

The following table provides details of the Company’s reserve for doubtful receivables:

	Year ended December 31,
	2015			2016			2017
Opening balance as of January 1	$15,192			$	11,530		$	15,519
Additions due to acquisitions		—			—			235
Additions charged to cost and expense	2449				7,282			9,819
Deductions/effect of exchange rate fluctuations		(6,111	)		(3,293	)		(1,913	)
Closing balance	$	11,530		$	15,519		$	23,660

Fair value measurements (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Fair Value of Assets and Liabilities Measured on Recurring Basis

	As of December 31, 2016
			Fair Value Measurements at Reporting Date Using
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Other Unobservable Inputs
	Total		(Level 1)		(Level 2)		(Level 3)
Assets
Derivative instruments (Notes a, c)	$	55,386	$	—	$	55,386	$	—
Total	$	55,386	$	—	$	55,386	$	—
Liabilities
Earn-out consideration (Notes b, d)	$	22,435	$	—	$	—	$	22,435
Derivative instruments (Notes b, c)		17,353		—		17,353		—
Total	$	39,788	$	—	$	17,353	$	22,435
Redeemable non-controlling interest (Note e)	$	4,520	$	—	$	—	$	4,520

	As of December 31, 2017
			Fair Value Measurements at Reporting Date Using
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Other Unobservable Inputs
	Total		(Level 1)		(Level 2)		(Level 3)
Assets
Derivative instruments (Notes a, c)	$	73,098	$	—	$	73,098	$	—
Total	$	73,098	$	—	$	73,098	$	—
Liabilities
Earn-out consideration (Notes b, d)	$	24,732	$	—	$	—	$	24,732
Derivative instruments (Notes b, c)		18,188		—		18,188		—
Total	$	42,920	$	—	$	18,188	$	24,732
Redeemable non-controlling interest (Note e)	$	4,750	$	—	$	—	$	4,750

(a)	Included in prepaid expenses and other current assets and other assets in the consolidated balance sheets.

(b)	Included in accrued expenses and other current liabilities and other liabilities in the consolidated balance sheets.

(c)	The Company values its derivative instruments based on market observable inputs, including both forward and spot prices for the relevant currencies and interest rate indices for relevant interest rates. The quotes are taken from an independent market database.

(d)

6. Fair Value Measurements (continued)

(e)

Fair Value of Earn-out Consideration

The following table provides a roll-forward of the fair value of earn-out consideration categorized as level 3 in the fair value hierarchy for the years ended December 31, 2016 and 2017:

	As of December 31
	2016			2017
Opening balance	$	22,820		$	22,435
Earn-out consideration payable in connection with acquisitions		14,550			10,720
Payments made of earn-out consideration		(1,611	)		(7,239	)
Change in fair value (note a)		(14,869	)		(3,695	)
Other (note b)		1,545			2,511
Ending balance	$	22,435		$	24,732

(a)	Changes in the fair value of earn-out consideration are reported in other operating (income) expense, net in the consolidated statements of income.

(b)

Derivative financial instruments (Tables)

12 Months Ended

Dec. 31, 2017

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Aggregate Notional Principal Amounts of Outstanding Derivative Financial Instruments with Related Balance Sheet Exposure

The following table presents the aggregate notional principal amounts of outstanding derivative financial instruments together with the related balance sheet exposure:

	Notional principal amounts (note a)				Balance sheet exposure asset (liability) (note b)
	As of December 31, 2016		As of December 31, 2017		As of December 31, 2016			As of December 31, 2017
Foreign exchange forward contracts denominated in:
United States Dollars (sell) Indian Rupees (buy)	$	1,108,400	$	1,289,400	$	6,669		$	54,398
United States Dollars (sell) Mexican Peso (buy)		9,120		9,000		(187	)		(441	)
United States Dollars (sell) Philippines Peso (buy)		70,050		76,650		(1,036	)		69
Euro (sell) United States Dollars (buy)		138,613		170,542		9,180			(2,069	)
Pound Sterling (buy) United States Dollars (sell)		—		24,041		—			253
Euro (sell) Romanian Leu (buy)		29,805		35,826		(152	)		(892	)
Japanese Yen (sell) Chinese Renminbi (buy)		77,267		60,768		(742	)		1,918
Pound Sterling (sell) United States Dollars (buy)		104,142		80,871		14,228			(2,478	)
Australian Dollars (sell) United States Dollars (buy)		114,412		136,092		2,328			(5,180	)
Interest rate swaps (floating to fixed)		456,810		432,117		7,746			9,332
					$	38,034		$	54,910

(a)

(b)	Balance sheet exposure is denominated in U.S. dollars and denotes the mark-to-market impact of the derivative financial instruments on the reporting date.

Fair Values of Derivative Instruments and Location in Financial Statements

7. Derivative financial instruments (Continued)

The fair values of the Company’s derivative instruments and their location in the Company’s financial statements are summarized in the table below:

	Cash flow hedges				Non-designated
	As of December 31, 2016		As of December 31, 2017		As of December 31, 2016		As of December 31, 2017
Assets
Prepaid expenses and other current assets	$	33,921	$	43,557	$	809	$	4,635
Other assets	$	20,657	$	24,906	$	—	$	—
Liabilities
Accrued expenses and other current liabilities	$	4,540	$	10,092	$	237	$	254
Other liabilities	$	12,576	$	7,842	$	—	$	—

Cash Flow Hedges, Gains (Losses) Recorded as Component of Other Comprehensive Income (Loss) or Other Comprehensive Income

In connection with cash flow hedges, the gains (losses) recorded as a component of other comprehensive income (loss), or OCI, and the related tax effects are summarized below:

	Year ended December 31,
	2015									2016									2017
	Before- Tax amount			Tax (Expense) or Benefit			Net of tax Amount			Before- Tax amount			Tax (Expense) or Benefit			Net of tax Amount			Before- Tax amount		Tax (Expense) or Benefit			Net of tax Amount
Opening balance	$	(66,786	)	$	23,646		$	(43,140	)	$	(30,090	)	$	9,830		$	(20,260	)	$	37,461	$	(13,979	)	$	23,482
Net gains (losses) reclassified into statement of income on completion of hedged transactions		(42,106	)		15,346			(26,760	)		(6,799	)		409			(6,390	)		54,494		(17,725	)		36,769
Changes in fair value of effective portion of outstanding derivatives, net		(5,410	)		1,530			(3,880	)		60,752			(23,400	)		37,352			67,562		(18,182	)		49,380
Gain (loss) on cash flow hedging derivatives, net		36,696			(13,816	)		22,880			67,551			(23,809	)		43,742			13,068		(457	)		12,611
Closing balance	$	(30,090	)	$	9,830		$	(20,260	)	$	37,461		$	(13,979	)	$	23,482		$	50,529	$	(14,436	)	$	36,093

Gains (Losses) Recorded as Component of Other Comprehensive Income (Loss) or Other Comprehensive Income

7. Derivative financial instruments (Continued)

The gains or losses recognized in other comprehensive income (loss) and their effects on financial performance are summarized below:

Derivatives in Cash Flow Hedging Relationships	Amount of Gain (loss) recognized in OCI on Derivatives (Effective Portion)							Location of Gain (loss) reclassified from OCI into Statement of Income (Effective Portion)	Amount of Gain (loss) reclassified from OCI into Statement of Income (Effective Portion)
	Year ended December 31,								Year ended December 31,
	2015			2016		2017			2015			2016			2017
Forward foreign exchange contracts	$	(5,410	)	$	54,664	$	66,037	Revenue	$	13,667		$	12,859		$	5,858
Interest rate swaps	$	—		$	6,088	$	1,525	Cost of revenue	$	(44,634	)	$	(14,223	)	$	37,849
								Selling, general and administrative expenses	$	(11,139	)	$	(3,765	)	$	10,849
								Interest expense	$	—		$	(1,670	)	$	(62	)
	$	(5,410	)	$	60,752	$	67,562		$	(42,106	)	$	(6,799	)	$	54,494

Gain (loss) recognized in income on the ineffective portion of derivatives and the amount excluded from effectiveness testing is $0 as of December 31, 2015, 2016 and 2017.

Non-designated Hedges

Derivatives not designated as hedging instruments	Location of Gain (Loss) recognized in Statement of Income on Derivatives	Amount of Gain (Loss) recognized in Statement of Income on Derivatives
		Year ended December 31,
		2015		2016		2017
Forward foreign exchange contracts (Note a)	Foreign exchange gains (losses), net	$	6,566	$	2,921	$	16,696
		$	6,566	$	2,921	$	16,696

(a)

Prepaid expenses and other current assets (Tables)

12 Months Ended

Dec. 31, 2017

Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]

Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consist of the following:

	As of December 31,
	2016		2017
Advance income and non-income taxes	$	50,676	$	51,832
Deferred transition costs		45,252		62,029
Derivative instruments		34,730		48,192
Prepaid expenses		22,222		16,944
Customer acquisition cost		11,126		19,327
Employee advances		6,880		5,014
Deposits		2,688		4,719
Advances to suppliers		10,059		2,705
Others		5,516		25,580
	$	189,149	$	236,342

Property, plant and equipment, net (Tables)

12 Months Ended

Dec. 31, 2017

Property Plant And Equipment [Abstract]

Property, plant and equipment, net

Property, plant and equipment, net consist of the following:

	As of December 31,
	2016			2017
Land	$	9,635		$	10,209
Buildings		44,487			46,007
Furniture and fixtures		37,421			43,091
Computer equipment and servers		187,119			210,725
Plant, machinery and equipment		84,677			92,981
Computer software		119,648			137,459
Leasehold improvements		92,313			102,072
Vehicles		6,753			6,418
Capital work in progress		18,501			17,069
Property, plant and equipment, gross	$	600,554		$	666,031
Less: accumulated depreciation, amortization and impairment		(407,336	)		(459,001	)
Property, plant and equipment, net	$	193,218		$	207,030

Goodwill and intangible assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill And Intangible Assets Disclosure [Abstract]

Changes in Goodwill

The following table presents the changes in goodwill for the years ended December 31, 2016 and 2017:

	As of December 31,
	2016			2017
Opening balance	$	1,038,346		$	1,069,408
Goodwill relating to acquisitions consummated during the period		51,535			229,745
Goodwill relating to divestitures during the period		(2,226	)		—
Impact of measurement period adjustments		(59	)		(106	)
Effect of exchange rate fluctuations		(18,188	)		38,075
Closing balance	$	1,069,408		$	1,337,122

Goodwill Allocated to Reporting Units

Goodwill has been allocated to the following reporting units, which represent different business units of the Company, as follows:

	As of December 31,
	2016		2017
India	$	493,084	$	735,596
China		58,139		60,171
Europe		36,584		41,775
Americas		48,713		57,021
IT services		432,888		442,559
	$	1,069,408	$	1,337,122

Intangible Assets Acquired Either Individually or with Group of Other Assets or in Business Combination

The Company’s intangible assets acquired either individually or with a group of other assets or in a business combination are as follows:

	As of December 31, 2016						As of December 31, 2017
	Gross carrying amount		Accumulated amortization & Impairment		Net		Gross carrying amount		Accumulated amortization & Impairment		Net
Customer-related intangible assets	$	312,041	$	260,018	$	52,023	$	369,173	$	293,029	$	76,144
Marketing-related intangible assets		45,098		30,571		14,527		52,443		39,212		13,231
Technology-related intangible assets		26,116		21,026		5,090		54,189		28,278		25,911
Other intangible assets		2,875		2,466		409		3,081		2,314		767
Intangible assets under development		6,897		—		6,897		15,537		—		15,537
	$	393,027	$	314,081	$	78,946	$	494,423	$	362,833	$	131,590

Estimated Amortization Schedule of Intangible Assets for Future Periods

10. Goodwill and intangible assets (Continued)

The estimated amortization schedule for the Company’s intangible assets for future periods is set out below:

For the year ending December 31:
2018	$	38,569
2019		27,518
2020		26,831
2021		13,080
2022 and beyond		25,592
	$	131,590

Other assets (Tables)

12 Months Ended

Dec. 31, 2017

Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]

Other assets

Other assets consist of the following:

	As of December 31,
	2016		2017
Customer acquisition cost	$	30,996	$	37,017
Advance income and non-income taxes		60,203		63,474
Deferred transition costs		74,462		77,255
Deposits		29,853		32,174
Derivative instruments		20,657		24,906
Prepaid expenses		3,179		2,849
Accounts receivable due after one year		3,272		1,624
Others		19,706		22,870
	$	242,328	$	262,169

Leases (Tables)

12 Months Ended

Dec. 31, 2017

Leases [Abstract]

Future Minimum Lease Payments under Operating Lease Arrangements

operating lease agreements that expire at various dates. Future minimum lease payments under these agreements are as follows

As of December 31:
2018	$	59,269
2019		54,844
2020		47,788
2021		43,692
2022		38,275
2023 and beyond		122,150
Total minimum lease payments	$	366,018

Accrued expenses and other current liabilities (Tables)

12 Months Ended

Dec. 31, 2017

Payables And Accruals [Abstract]

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following:

	As of December 31,
	2016		2017
Accrued expenses	$	163,400	$	204,997
Accrued employee cost		179,360		204,506
Deferred transition revenue		50,552		52,233
Statutory liabilities		36,878		36,283
Retirement benefits		17,616		21,074
Derivative instruments		4,777		10,346
Advance from customers		21,969		25,476
Earn-out consideration		6,885		14,928
Other liabilities		15,461		13,093
Capital lease obligations		1,349		1,546
	$	498,247	$	584,482

Long-term debt (Tables)

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Maturity Profile of Term Loan, Net of Debt Amortization Expense

The maturity profile of the term loan, net of debt amortization expense, is as follows:

Year ended	Amount
2018	$	39,226
2019		39,272
2020		619,654
Total	$	698,152

Other liabilities (Tables)

12 Months Ended

Dec. 31, 2017

Other Liabilities Disclosure [Abstract]

Other liabilities

Other liabilities consist of the following:

	As of December 31,
	2016		2017
Accrued employee cost	$	3,976	$	14,020
Deferred transition revenue		72,560		70,900
Retirement benefits		39,020		40,520
Derivative instruments		12,576		7,842
Amount received from GE under indemnification arrangement, pending adjustment		3,159		3,359
Advance from customers		2,371		790
Earn-out consideration		15,550		9,804
Others		11,078		18,710
Capital lease obligations		2,500		2,664
	$	162,790	$	168,609

Employee benefit plans (Tables)

12 Months Ended

Dec. 31, 2017

Funded Status of Defined Benefit Plans and Amount Recognized

	As of December 31,
	2016			2017
Change in benefit obligation
Projected benefit obligation at the beginning of the year	$	35,617		$	45,283
Service cost		5,661			7,735
Actuarial loss		6,749			4,493
Interest cost		2,585			3,252
Liabilities assumed on acquisition		693
Benefits paid		(4,967	)		(5,367	)
Special termination benefit	-				57
Effect of exchange rate changes		(1,055	)		2,641
Projected benefit obligation at the end of the year	$	45,283		$	58,094
Change in fair value of plan assets
Fair value of plan assets at the beginning of the year	$	28,549		$	30,871
Employer contributions		5,776			15,176
Actual gain on plan assets		1,777			2,746
Assets assumed on acquisition		170			0
Actuarial gain		—			11
Benefits paid		(4,897	)		(5,301	)
Effect of exchange rate changes		(504	)		2,057
Fair value of plan assets at the end of the year	$	30,871		$	45,560

Amounts Included in Other Comprehensive Income (Loss)

Amounts included in other comprehensive income (loss) as of December 31, 2016 and 2017 were as follows:

	As of December 31,
	2016			2017
Net actuarial loss		(8,979	)		(12,228	)
Deferred tax assets		2,759			2,221
Other comprehensive income, net		(6,220	)		(10,007	)

Changes in Accumulated Other Comprehensive Income (Loss)

Changes in other comprehensive income (loss) during the year ended December 31, 2017 were as follows:

	2017
Net actuarial loss	$	(4,182	)
Amortization of net actuarial loss		1,177
Deferred income taxes		(670	)
One-time cost		211
Effect of exchange rate changes		(323	)
Other comprehensive income (loss), net	$	(3,787	)

Net Defined Benefit Plan Costs

Net defined benefit plan costs for the years ended December 31, 2015, 2016 and 2017 include the following components:

	Year ended December 31,
	2015			2016			2017
Service costs	$	5,578		$	5,661		$	7,735
Interest costs		2,629			2,585			3,252
Amortization of actuarial loss		330			(113	)		1,177
Expected return on plan assets		(2,154	)		(2,043	)		(2,412	)
One-time cost		—			—			209
Special termination benefits		—			—			426
Net defined benefit plan costs	$	6,383		$	6,090		$	10,387

Fair Values of Plan Assets

The fair values of the Company’s plan assets as of December 31, 2016 and 2017 by asset category are as follows:

	Total
	As of December 31, 2017
	Fair Value Measurements at Reporting Date Using
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Other Unobservable Inputs
	Total		(Level 1)		(Level 2)		(Level 3)
Asset Category
Cash	$	472	$	472	$	—	$	—
Fixed income securities (Note a)		42,328		3,419		38,909		—
Other securities (Note b)		2,760		2,437		323		—
Total	$	45,560	$	6,328	$	39,232	$	—

	Total
	As of December 31, 2016
	Fair Value Measurements at Reporting Date Using
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Other Unobservable Inputs
	Total		(Level 1)		(Level 2)		(Level 3)
Asset Category
Cash	$	4,809	$	4,809	$	—	$	—
Fixed income securities (Note a)		23,659		3,001		20,658		—
Other securities (Note b)		2,403		2,191		212		—
Total	$	30,871	$	10,001	$	20,870	$	—

(a)	Includes investments in funds that invest 100% of their assets in fixed income securities such as money market instruments, government securities and public and private bonds.

(b)	Includes investments in funds that invest primarily in fixed income securities and the remaining portion in equity securities.

Benefit Plan Payments Reflect Expected Future Service

The expected benefit plan payments set forth below reflect expected future service:

Year ending December 31,
2018	$	8,469
2019		8,823
2020		9,330
2021		9,946
2022		10,118
2023 - 2027		48,107
	$	94,793

Amount Contributed to Defined Contribution Plans in Various Jurisdictions

During the years ended December 31, 2015, 2016 and 2017, the Company contributed the following amounts to defined contribution plans in various jurisdictions:

	Year ended December 31,
	2015		2016		2017
India	$	15,915	$	19,074	$	22,242
U.S.		8,148		10,379		11,147
U.K.		4,453		6,593		7,823
China		14,511		15,512		15,950
Other regions		4,690		4,684		4,059
Total	$	47,717	$	56,242	$	61,221

Benefit Obligations Of Gratuity Plan

Weighted Average Assumptions used to Determine Benefit Obligations and Plan Costs

The weighted average assumptions used to determine the benefit obligations of the Gratuity Plan as of December 31, 2016 and 2017 are presented below:

	As of December 31,
	2016	2017
Discount rate	7.10% - 7.5%	7.40% - 7.60%
Rate of increase in compensation per annum	5.20%-11.00%	5.20%-11.00%

Gratuity Plan Costs

Weighted Average Assumptions used to Determine Benefit Obligations and Plan Costs

The weighted average assumptions used to determine the Gratuity Plan costs for the years ended December 31, 2015, 2016 and 2017 are presented below:

	Year ended December 31,
	2015	2016	2017
Discount rate	8.50% - 8.55%	8.30% - 8.45%	7.10% - 7.5%
Rate of increase in compensation per annum	5.20% - 11.00%	5.20% - 11.00%	5.20% - 11.00%
Expected long-term rate of return on plan assets per annum	8.50%	7.50%	7.50%

Benefit Obligations Of Mexican Plan

Weighted Average Assumptions used to Determine Benefit Obligations and Plan Costs

The weighted average assumptions used to determine the benefit obligations of the Mexican Plan as of December 31, 2016 and 2017 are presented below:

	Year ended December 31,
	2016			2017
Discount rate		6.80	%		7.60	%
Rate of increase in compensation per annum		5.50	%		5.50	%

Mexican Plan Costs

Weighted Average Assumptions used to Determine Benefit Obligations and Plan Costs

The weighted average assumptions used to determine the costs of the Mexican Plan for the years ended December 31, 2015, 2016 and 2017 are presented below:

	Year ended December 31,
	2015			2016			2017
Discount rate		6.50	%		6.50	%		6.80	%
Rate of increase in compensation per annum		5.50	%		5.50	%		5.50	%
Expected long-term rate of return on plan assets per annum		0.00	%		0.00	%		0.00	%

Benefit Obligations Of Japan Plan

Weighted Average Assumptions used to Determine Benefit Obligations and Plan Costs

17. Employee benefit plans (Continued)

The weighted average assumptions used to determine the benefit obligation of the Japan Plan as of December 31, 2016 and 2017 are presented below:

	Year ended December 31,
	2016	2017
Discount rate	0.08% - 1.30%	0.113%-0.789%
Rate of increase in compensation per annum	0.00% - 3.55%	0.00% - 3.55%

Japan Plan Costs

Weighted Average Assumptions used to Determine Benefit Obligations and Plan Costs

The weighted average assumptions used to determine the costs of the Japan Plan for the years ended December 31, 2015, 2016 and 2017 are presented below:

	Year ended December 31,
	2015	2016	2017
Discount rate	0.20% - 1.30%	0.24% - 1.30%	0.08% - 1.30%
Rate of increase in compensation per annum	0.00% - 3.55%	0.00% - 3.55%	0.00% - 3.55%
Expected long-term rate of return on plan assets per annum	2.69% - 3.44%	0.00% - 3.77%	0.00% - 3.09%

Stock-based compensation (Tables)

12 Months Ended

Dec. 31, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Share-based Payment Award, Stock Options Granted, Valuation Assumptions

The following table shows the significant assumptions used in connection with the determination of the fair value of options granted in 2015, 2016 and 2017:

	2015		2016		2017
Dividend yield		—		—		0.97%
Expected life (in months)	84		84		84
Risk-free rate of interest for expected life	1.99%		1.42% - 1.56%		2.25%
Volatility	34.97%		25.60% - 27.22%		24.28%

Summary of Stock Option Activity

A summary of stock option activity during the years ended December 31, 2015, 2016 and 2017 is set out below:

	Year ended December 31, 2015
	Shares arising out of options			Weighted average exercise price		Weighted average remaining contractual life (years)		Aggregate intrinsic value
Outstanding as of January 1, 2015		7,371,727		$	15.44		5.9	$	—
Granted		170,000			22.77		—		—
Forfeited		(125,000	)		19.35		—		—
Expired		(1,277	)		14.32		—		—
Exercised		(1,428,605	)		9.49		—		22,122
Outstanding as of December 31, 2015		5,986,845		$	16.99		5.8	$	48,661
Vested as of December 31, 2015 and expected to vest thereafter (Note a)		5,754,969		$	16.76		5.8	$	47,325
Vested and exercisable as of December 31, 2015		2,183,846		$	12.67		2.7	$	26,892
Weighted average grant-date fair value of options granted during the period	$	9.15

18. Stock-based compensation (Continued)

	Year ended December 31, 2016
	Shares arising out of options			Weighted average exercise price		Weighted average remaining contractual life (years)		Aggregate intrinsic value
Outstanding as of January 1, 2016		5,986,845		$	16.99		5.8	$	—
Granted		860,000			26.80		—		—
Forfeited		(145,000	)		17.77		—		—
Expired		—			—		—		—
Exercised		(994,155	)		14.98		—		9,301
Outstanding as of December 31, 2016		5,707,690		$	18.65		5.8	$	34,641
Vested as of December 31, 2016 and expected to vest thereafter (Note a)		5,457,701		$	18.42		5.8	$	34,150
Vested and exercisable as of December 31, 2016		2,746,191		$	15.62		4.0	$	23,960
Weighted average grant-date fair value of options granted during the period	$	8.50


	Year ended December 31, 2017
	Shares arising out of options			Weighted average exercise price		Weighted average remaining contractual life (years)		Aggregate intrinsic value
Outstanding as of January 1, 2017		5,707,690		$	18.65		5.8	$	—
Granted		250,000			24.74		—		—
Forfeited		(80,000	)		20.63		—		—
Expired		—			—		—		—
Exercised		(743,045	)		14.50		—		12,636
Outstanding as of December 31, 2017		5,134,645		$	19.52		5.6	$	62,743
Vested as of December 31, 2017 and expected to vest thereafter (Note a)		4,988,875		$	19.36		5.6	$	61,779
Vested and exercisable as of December 31, 2017		2,203,146		$	16.17		4.1	$	34,303
Weighted average grant-date fair value of options granted during the period	$	6.62

(a)	Options expected to vest reflect an estimated forfeiture rate.

Summary of Restricted Share Units Granted

A summary of RSUs granted during the years ended December 31, 2015, 2016 and 2017 is set out below:

	Year ended December 31, 2015
	Number of Restricted Share Units			Weighted Average Grant Date Fair Value
Outstanding as of January 1, 2015		488,418		$	15.36
Granted		53,546			20.88
Vested (Note b)		(351,338	)		15.29
Forfeited		(33,236	)		14.00
Outstanding as of December 31, 2015		157,390		$	17.67
Expected to vest (Note a)		147,226

	Year ended December 31, 2016
	Number of Restricted Share Units			Weighted Average Grant Date Fair Value
Outstanding as of January 1, 2016		157,390		$	17.67
Granted		95,553			25.49
Vested (Note c)		(133,903	)		20.66
Forfeited		(1,135	)		14.18
Outstanding as of December 31, 2016		117,905		$	20.65
Expected to vest (Note a)		107,366
	Year ended December 31, 2017
	Number of Restricted Share Units			Weighted Average Grant Date Fair Value
Outstanding as of January 1, 2017		117,905		$	20.65
Granted		1,533,836			26.36
Vested (Note d)		(45,248	)		18.31
Forfeited		(1,242	)		25.53
Outstanding as of December 31, 2017		1,605,251		$	26.17
Expected to vest (Note a)		1,371,567

(a)	RSUs expected to vest reflect an estimated forfeiture rate.

(b)	Vested RSUs were net settled by issuing 199,949 shares (net of minimum statutory tax withholding). 53,546 RSUs vested in the year ended December 31, 2015, 53,023 shares in respect of which were issued in 2017 after withholding shares to the extent of minimum statutory withholding taxes.

(c)

(d)	Vested RSUs were net settled by issuing 32,395 shares (net of minimum statutory tax withholding).

Summary of Performance Units Activity

A summary of PU activity during the years ended December 31, 2015, 2016 and 2017 is set out below:

	Year ended December 31, 2015
	Number of Performance Units			Weighted Average Grant Date Fair Value		Maximum Shares Eligible to Receive
Outstanding as of January 1, 2015		1,292,750		$	16.78		2,648,626
Granted		1,375,650			22.72		2,965,475
Vested (Note b)		(855	)		16.78		(855	)
Forfeited		(136,216	)		17.82		(156,194	)
Adjustment due to achievement of lower-than-target performance (Note c)		(32,007	)		20.45
Adjustment due to achievement of lower-than-maximum performance (Note d)							(2,957,730	)
Outstanding as of December 31, 2015		2,499,322		$	19.95		2,499,322
Expected to vest (Note a)		2,184,906

18. Stock-based compensation (Continued)

	Year ended December 31, 2016
	Number of Performance Units			Weighted Average Grant Date Fair Value		Maximum Shares Eligible to Receive
Outstanding as of January 1, 2016		2,499,322		$	19.95		2,499,322
Granted		1,518,374			27.93		3,343,335
Vested		—			—		—
Forfeited		(252,842	)		21.88		(325,817	)
Adjustment upon final determination of level of performance goal achievement (Note e)		7,274			22.72
Adjustment upon final determination of level of performance goal achievement (Note e)							7,274
Outstanding as of December 31, 2016		3,772,128		$	23.04		5,524,114
Expected to vest (Note a)		2,226,489
	Year ended December 31, 2017
	Number of Performance Units			Weighted Average Grant Date Fair Value		Maximum Shares Eligible to Receive
Outstanding as of January 1, 2017		3,772,128		$	23.04		5,524,114
Granted		1,811,292			25.22		3,622,584
Vested (Note f)		(1,136,047)			16.78		(1,136,047)
Forfeited (Note g)		(1,583,913	)		27.57		(1,627,313	)
Adjustment upon final determination of level of performance goal achievement (Note h)		37,480			25.22
Adjustment upon final determination of level of performance goal achievement (Note i)							(3,482,398)
Outstanding as of December 31, 2017		2,900,940		$	24.40		2,900,940
Expected to vest (Note a)		2,657,685

(a)	PUs expected to vest are based on the probable achievement of the performance targets after considering an estimated forfeiture rate.

(b)	Vested PUs were net settled upon vesting by issuing 590 shares (net of minimum statutory tax withholding).

18. Stock-based compensation (Continued)

(c)

(d)

(e)	Represents an adjustment made in March 2016 to the number of shares underlying the PUs granted in 2015 upon certification of the level of achievement of the performance targets for such awards.

(f)	Vested PUs were net settled upon vesting by issuing 731,701 shares (net of minimum statutory tax withholding).

(g)	Includes 1,443,624 target shares underlying PUs granted in 2016 which were forfeited for failure to achieve all of the threshold performance targets under such awards as certified by the compensation committee based on the Company’s audited financial statements for the year ended December 31, 2016.

(h)	Represents a 2.7% increase in the number of target shares as a result of achievement of higher-than-target performance for certain PUs granted in 2017, partially offset by a 12.5% reduction as a result of achievement of lower-than-target performance for certain PUs granted in 2017.

(i)

Earnings per share (Tables)

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Earnings Per share

	Year ended December 31,
	2015		2016		2017
Net income available to Genpact Limited common shareholders	$	239,817	$	269,684	$	263,111
Weighted average number of common shares used in computing basic earnings per common share		216,606,542		206,861,536		193,864,755
Dilutive effect of stock-based awards		2,538,502		3,264,487		3,184,797
Weighted average number of common shares used in computing dilutive earnings per common share		219,145,044		210,126,023		197,049,552
Earnings per common share attributable to Genpact Limited common shareholders
Basic	$	1.11	$	1.30	$	1.36
Diluted	$	1.09	$	1.28	$	1.34

Cost of revenue (Tables)

12 Months Ended

Dec. 31, 2017

Selling General And Administrative Expenses [Abstract]

Cost of revenue

Cost of revenue consists of the following:

	Year ended December 31,
	2015		2016		2017
Personnel expenses	$	1,013,209	$	1,061,501	$	1,155,745
Operational expenses		432,535		446,922		481,012
Depreciation and amortization		47,803		46,284		46,947
	$	1,493,547	$	1,554,707	$	1,683,704

Selling, general and administrative expenses (Tables)

12 Months Ended

Dec. 31, 2017

Selling, General and Administrative Expenses

Selling, general and administrative expenses consist of the following:

	Year ended December 31,
	2015		2016		2017
Personnel expenses	$	430,088	$	469,956	$	501,445
Operational expenses		169,042		174,060		178,573
Depreciation and amortization		8,984		9,013		9,829
	$	608,114	$	653,029	$	689,847

Other operating (income) expense, net (Tables)

12 Months Ended

Dec. 31, 2017

Other Operating (Income) Expense, Net

	Year ended December 31,
	2015			2016			2017
Other operating (income) expense	$	(2,515	)	$	(1,266	)	$	(7,277	)
Provision for impairment of intangible assets and property, plant and equipment		10,714			11,195			9,311
Change in fair value of earn-out consideration and deferred consideration (relating to business acquisitions)		(11,521	)		(14,869	)		(3,695	)
Other operating (income) expense, net	$	(3,322	)	$	(4,940	)	$	(1,661	)

Interest income (expense), net (Tables)

12 Months Ended

Dec. 31, 2017

Banking And Thrift Interest [Abstract]

Interest Income (Expense), Net

Interest income (expense), net consists of the following:

	Year ended December 31,
	2015			2016			2017
Interest income	$	8,676		$	7,247		$	8,182
Interest expense		(29,828	)		(23,431	)		(39,917	)
Loss on extinguishment of debt		(10,115	)		-			-
Interest income (expense), net	$	(31,267	)	$	(16,184	)	$	(31,735	)

Income taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Income Tax Expense (Benefit)

Income tax expense (benefit) for the years ended December 31, 2015, 2016 and 2017 is allocated as follows:

	Year ended December 31,
	2015			2016			2017

Income from continuing operations	$	61,937		$	62,098		$	59,742
Other comprehensive Income:
Unrealized gains (losses) on cash flow hedges		13,816			23,809			457
Retirement benefits		1,304			(1,885	)		670
Additional paid in capital:
Excess tax benefit on stock-based compensation		(6,560	)		—			—
Retained earnings:
Deferred tax assets recognized on early adoption of ASU 2016-09		—			(24,912	)		—

Components of Income before Income Tax Expense from Continuing Operations

The components of income before income tax expense from continuing operations are as follows:

	Year ended December 31,
	2015		2016		2017
Domestic (U.S.)	$	23,122	$	44,110	$	8,440
Foreign (Non-U.S.)		278,632		285,535		312,143
Income before income taxes	$	301,754	$	329,645	$	320,583

Income Tax Expense (Benefit) Attributable to Income from Continuing Operations

Income tax expense (benefit) attributable to income from continuing operations consists of:

	Year ended December 31,
	2015			2016			2017
Current taxes:
Domestic (U.S. federal taxes)	$	12,142		$	78		$	3,380
Domestic (U.S. state taxes)		301			1,069			1,268
Foreign (Non-U.S.)		68,207			30,497			65,485
	$	80,650		$	31,644		$	70,133
Deferred taxes:
Domestic (U.S. federal taxes)	$	(5,396	)	$	11,379		$	3,549
Domestic (U.S. state taxes)		344			(459	)		(2,809	)
Foreign (Non-U.S.)		(13,661	)		19,534			(11,131	)
	$	(18,713	)	$	30,454		$	(10,391	)
Total income tax expense (benefit)	$	61,937		$	62,098		$	59,742

Income Tax Expense (Benefit) Computed by Applying United States Federal Statutory Income Tax Rate to Income Before Income Taxes

	Year ended December 31,
	2015			2016			2017
Income before income tax expense	$	301,754		$	329,645		$	320,583
Statutory tax rates		35	%		35	%		35	%
Computed expected income tax expense		105,614			115,376			112,204
Increase (decrease) in income taxes resulting from:
Foreign tax rate differential		(16,550	)		(18,574	)		(25,224	)
Tax benefit from tax holiday		(38,039	)		(32,893	)		(35,814	)
Non-deductible expenses		1,884			2,295			1,146
Effect of change in tax rates		1,436			353			2,778
Change in valuation allowance		(33	)		(4,830	)		9,041
Unrecognized tax benefits		6,272			(627	)		1,611
Other*		1,353			998			(6,000	)
Reported income tax expense (benefit)	$	61,937		$	62,098		$	59,742
*During 2017, following the transfer/closure of certain affiliated entities, deferred tax liabilities recorded against the outside basis difference amounting to $9,600 were reversed. It was not more likely than not that the resulting net deferred tax asset would be realized. Therefore, a full valuation allowance was established to offset the reduction in deferred tax liabilities.

Components of Deferred Tax Balances

The components of the Company’s deferred tax balances as of December 31, 2016 and 2017 are as follows:

	As of December 31,
	2016			2017
Deferred tax assets
Net operating loss carryforwards	$	52,997		$	55,500
Accrued liabilities and other expenses		19,840			41,177
Provision for doubtful debts		6,419			10,509
Property, plant and equipment		3,445			1,270
Unrealized losses on cash flow hedges, Net		558			275
Share-based compensation		19,054			19,789
Retirement benefits		5,067			5,817
Deferred revenue		44,892			22,948
Tax credit carryforwards		34,509			35,322
Other		8,876			11,571
Gross deferred tax assets	$	195,657		$	204,178
Less: valuation allowance		(14,746	)		(24,549	)
Total deferred tax assets	$	180,911		$	179,629
Deferred tax liabilities
Intangible assets	$	13,519		$	15,954
Property, plant and equipment		2,745			1,131
Deferred cost		41,950			33,816
Investments in foreign subsidiaries not indefinitely reinvested		29,546			18,949
Unrealized gains on cash flow hedges, net		14,350			14,711
Other		11,073			24,886
Total deferred tax liabilities	$	113,183		$	109,447
Net deferred tax asset	$	67,728		$	70,182

	As of December 31,
Classified as	2016		2017
Deferred tax assets
Non-current	$	70,143	$	76,929
Deferred tax liabilities
Non-current		2,415		6,747
	$	67,728	$	70,182

Change in Total Valuation Allowance for Deferred Tax Assets

The change in the total valuation allowance for deferred tax assets as of December 31, 2015, 2016 and 2017 is as follows:

	Year ended December 31,
	2015			2016			2017
Opening valuation allowance	$	21,094		$	20,091		$	14,746
Reduction during the year		(3,499	)		(7,299	)		(3,957	)
Addition during the year		2,496			1,954			13,760
Closing valuation allowance	$	20,091		$	14,746		$	24,549

Remaining Tax Loss Carry Forwards Expiration

The Company’s remaining tax loss carryforwards expire as set forth in the table below:

	US – Federal		Europe		Others
Year ending December 31,
2018	$	—	$	—	$	20
2019		—		—		72
2020		—		1,872		62
2021		—		581		2,084
2022		—		5,253		60
2023		—		8,500		953
2024		—		1,213		7,941
2025		—		28,222		9,647
2026		9,511		2,263		3,072
2027		9,913		—		2,053
2028		—		33		2,451
2034		—		—		1,027
	$	19,424	$	47,937	$	29,442

Foreign Tax Credit Expiry Period

As of December 31, 2017, the company had a total foreign tax credit carryforward of $33,220, which will expire as set forth in the table below:

Year ending December 31,	Amount
2023	$	893
2024		1,202
2025		15,552
2026		8,481
2027		5,362
2028		1,730
	$	33,220

25. Income taxes (Continued)

The following table summarizes activities related to our unrecognized tax benefits from January 1 to December 31 for each of 2015, 2016 and 2017:

	Year Ended December 31,
	2015			2016			2017
Opening balance at January 1	$	22,718		$	26,357		$	23,467
Increase related to prior year tax positions, including recorded in acquisition accounting		2,000			370			2,582
Decrease related to prior year tax positions		—			(1,506	)		(1,398	)
Decrease related to divestiture of business		—			(345	)		—
Decrease related to prior year tax position due to lapse of applicable statute of limitation		(820	)		(2,122	)		(1,019	)
Increase related to current year tax positions, including recorded in acquisition accounting		3,544			3,225			1,661
Decrease related to settlements with tax Authorities		—			(2,000	)		—
Effect of exchange rate changes		(1,085	)		(512	)		767
Closing balance at December 31	$	26,357		$	23,467		$	26,060

Segment reporting (Tables)

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Net Revenues for Service Type

Net revenues by service type are as follows:

	Year ended December 31,
	2015		2016		2017
Business process outsourcing	$	1,933,095	$	2,083,450	$	2,264,335
Information technology services		527,949		487,306		472,594
Total net revenues	$	2,461,044	$	2,570,756	$	2,736,929

Revenues from Clients Based on Industry Serviced

Revenues from clients based on the industry serviced are as follows:

	Year ended December 31,
	2015		2016		2017
Banking, financial services and insurance	$	1,030,584	$	1,055,704	$	1,105,731
Manufacturing, including pharmaceuticals and medical equipment manufacturing		878,570		958,779		1,002,973
Technology, healthcare and other services		551,890		556,273		628,225
Total net revenues	$	2,461,044	$	2,570,756	$	2,736,929

Net Revenues from Geographic Areas Based on Location of Service Delivery Centers

	Year ended December 31,
	2015		2016		2017
India	$	1,687,699	$	1,804,113	$	1,712,783
Asia, other than India		238,529		249,839		286,338
North and Latin America		304,879		282,434		455,059
Europe		229,937		234,370		282,749
Total net revenues	$	2,461,044	$	2,570,756	$	2,736,929

Property, Plant and Equipment, Net by Geographic Areas

26. Segment reporting (Continued)

Property, plant and equipment, net by geographic region are as follows:

	As of December 31,
	2016		2017
India	$	116,417	$	125,490
Asia, other than India		13,549		15,899
North and Latin America		44,633		38,438
Europe		18,619		27,203
Total	$	193,218	$	207,030

Quarterly financial data (unaudited) (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Data

	Three months ended									Year ended
	March 31, 2017		June 30, 2017			September 30, 2017		December 31, 2017		December 31, 2017
Total net revenues	$	622,995	$	670,697		$	708,824	$	734,413	$	2,736,929
Gross profit	$	239,658	$	255,404		$	279,633	$	278,530	$	1,053,225
Income from operations	$	79,096	$	80,031		$	97,451	$	72,049	$	328,627
Income before equity method investment activity, net and income tax expense	$	69,243	$	84,582		$	89,742	$	81,559	$	325,126
Net Income	$	52,440	$	69,102		$	73,161	$	66,138	$	260,841
Net (income) loss attributable to redeemable non-controlling interest	$	898	$	(156	)	$	584	$	944	$	2,270
Net income attributable to Genpact Limited common shareholders	$	53,338	$	68,946		$	73,745	$	67,082	$	263,111
Earnings per common share attributable to Genpact Limited common shareholders
Basic	$	0.27	$	0.36		$	0.38	$	0.35	$	1.36
Diluted	$	0.26	$	0.36		$	0.38	$	0.34	$	1.34
Weighted average number of common shares used in computing earnings per common share attributable to Genpact Limited common shareholders
Basic		199,069,528		191,469,593			192,124,366		192,795,534		193,864,755
Diluted		202,655,937		193,732,406			194,947,699		196,862,168		197,049,552

29. Quarterly financial data (unaudited) (Continued)

	Three months ended								Year ended
	March 31, 2016		June 30, 2016		September 30, 2016		December 31, 2016		December 31, 2016
Total net revenues	$	609,703	$	630,523	$	648,783	$	681,747	$	2,570,756
Gross profit	$	236,855	$	246,768	$	256,351	$	276,075	$	1,016,049
Income from operations	$	75,622	$	79,940	$	87,124	$	98,092	$	340,777
Income before equity method investment activity, net and income tax expense	$	72,664	$	81,818	$	87,360	$	95,502	$	337,343
Net income	$	58,505	$	64,788	$	68,188	$	76,066	$	267,547
Net (income) loss attributable to redeemable non-controlling interest	$	289	$	882	$	734	$	232	$	2,137
Net income attributable to Genpact Limited common shareholders	$	58,794	$	65,670	$	68,922	$	76,298	$	269,684
Earnings per common share attributable to Genpact Limited common shareholders
Basic	$	0.28	$	0.31	$	0.33	$	0.38	$	1.30
Diluted	$	0.27	$	0.31	$	0.33	$	0.38	$	1.28
Weighted average number of common shares used in computing earnings per common share attributable to Genpact Limited common shareholders
Basic		210,780,165		210,178,050		206,146,007		200,341,922		206,861,536
Diluted		213,892,964		213,803,134		209,376,683		203,431,310		210,126,023

Organization - Additional Information (Detail)	Dec. 31, 2017 Employee Country
Accounting Policies [Abstract]
Number of employees around the globe, minimum \| Employee	78,000
Number of countries in which entity operates \| Country	20

Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
General Electric Company
Schedule Of Significant Accounting Policies [Line Items]
Percentage of accounts receivables	11.00%	15.00%
Percentage of revenues	10.00%	14.00%	19.00%
Minimum
Schedule Of Significant Accounting Policies [Line Items]
Short term investment, maturity period	90 days
Maximum
Schedule Of Significant Accounting Policies [Line Items]
Short term investment, maturity period	1 year

Estimated Economic Useful Lives of Assets (Detail)	12 Months Ended
Estimated Economic Useful Lives of Assets (Detail)	Dec. 31, 2017
Buildings
Property Plant And Equipment [Line Items]
Property, plant and equipment, estimated useful lives	40 years
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property, plant and equipment, estimated useful lives	4 years
Computer Equipment and Servers
Property Plant And Equipment [Line Items]
Property, plant and equipment, estimated useful lives	4 years
Plant, Machinery and Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, estimated useful lives	4 years
Computer software \| Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, estimated useful lives	4 years
Computer software \| Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, estimated useful lives	7 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property, plant and equipment, estimated useful lives	10 years
Property, plant and equipment, estimated useful lives description	Lesser of lease period or 10 Years
Vehicles \| Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, estimated useful lives	3 years
Vehicles \| Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, estimated useful lives	4 years

Estimated Useful Lives of Intangible Assets Acquired/Developed (Detail)	12 Months Ended
	Dec. 31, 2017
Customer-Related Intangible Assets \| Maximum
Acquired Finite Lived Intangible Assets [Line Items]
Intangible assets estimated useful lives	14 years
Customer-Related Intangible Assets \| Minimum
Acquired Finite Lived Intangible Assets [Line Items]
Intangible assets estimated useful lives	1 year
Marketing-Related Intangible Assets \| Maximum
Acquired Finite Lived Intangible Assets [Line Items]
Intangible assets estimated useful lives	10 years
Marketing-Related Intangible Assets \| Minimum
Acquired Finite Lived Intangible Assets [Line Items]
Intangible assets estimated useful lives	1 year
Technology-related intangible assets \| Maximum
Acquired Finite Lived Intangible Assets [Line Items]
Intangible assets estimated useful lives	8 years
Technology-related intangible assets \| Minimum
Acquired Finite Lived Intangible Assets [Line Items]
Intangible assets estimated useful lives	2 years
Other Intangible Assets \| Maximum
Acquired Finite Lived Intangible Assets [Line Items]
Intangible assets estimated useful lives	5 years
Other Intangible Assets \| Minimum
Acquired Finite Lived Intangible Assets [Line Items]
Intangible assets estimated useful lives	3 years

Business Acquisitions - TandemSeven, Inc. - Additional Information (Detail) - USD ($) $ in Thousands			12 Months Ended
	Sep. 05, 2017	Jan. 08, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Payment for business acquisitions, net of cash acquired			$ 284,822	$ 45,162	$ 21,363
Goodwill			$ 1,337,122	$ 1,069,408	$ 1,038,346
Acquisition related cost		$ 164
Acquired assets		412
Liabilities assumed		$ 617
TandemSeven, Inc.
Business Acquisition [Line Items]
Date of acquisition	Sep. 05, 2017
Ownership percentage acquired	100.00%
Business combination estimated purchase consideration	$ 35,720
Payment for business acquisitions, net of cash acquired	31,866
Cash and cash equivalents	$ 3,854
Maximum measurement period for tax position evaluation	1 year
Acquired intangible assets, weighted average amortization period	2 years
Goodwill	$ 25,298
Acquisition related cost	932
Acquired assets	7,388
Liabilities assumed	1,206
Recognized net deferred tax asset	260
TandemSeven, Inc. \| Customer-Related Intangible Assets
Business Acquisition [Line Items]
Intangible assets	2,000
TandemSeven, Inc. \| Marketing-Related Intangible Assets
Business Acquisition [Line Items]
Intangible assets	1,700
TandemSeven, Inc. \| Technology-related intangible assets
Business Acquisition [Line Items]
Intangible assets	$ 800

Business Acquisitions - BrightClaim LLC and Associated Companies - Additional Information (Detail) - USD ($) $ in Thousands			12 Months Ended
	May 03, 2017	Jan. 08, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Payment for business acquisitions, net of cash acquired			$ 284,822	$ 45,162	$ 21,363
Goodwill			1,337,122	$ 1,069,408	$ 1,038,346
Acquisition related cost		$ 164
Acquired assets		412
Liabilities assumed		$ 617
Bright Claim LLC And Associated Companies
Business Acquisition [Line Items]
Date of acquisition	May 03, 2017
Ownership percentage acquired	100.00%
Payment for business acquisitions, net of cash acquired	$ 52,395
Cash and cash equivalents	4,002
Purchase consideration	$ 56,461		56,496
Business combination change in contingent consideration receivable			$ 35
Acquired intangible assets, weighted average amortization period	4 years
Goodwill	$ 42,638
Acquisition related cost	1,563
Acquired assets	10,367
Liabilities assumed	7,415
Recognized net deferred tax asset	2,728
Bright Claim LLC And Associated Companies \| Customer-Related Intangible Assets
Business Acquisition [Line Items]
Intangible assets	8,000
Bright Claim LLC And Associated Companies \| Marketing-Related Intangible Assets
Business Acquisition [Line Items]
Intangible assets	3,200
Bright Claim LLC And Associated Companies \| Technology-related intangible assets
Business Acquisition [Line Items]
Intangible assets	2,200
Bright Claim LLC And Associated Companies \| Other Intangible Assets
Business Acquisition [Line Items]
Intangible assets	$ 200

Business Acquisitions - RAGE Frameworks, Inc. - Additional Information (Detail) - USD ($) $ in Thousands			12 Months Ended
	Apr. 13, 2017	Jan. 08, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Payment for business acquisitions, net of cash acquired			$ 284,822	$ 45,162	$ 21,363
Goodwill			$ 1,337,122	$ 1,069,408	$ 1,038,346
Acquisition related cost		$ 164
Acquired assets		412
Liabilities assumed		$ 617
Rage Frameworks Inc
Business Acquisition [Line Items]
Date of acquisition	Apr. 13, 2017
Ownership percentage acquired	100.00%
Business combination estimated purchase consideration	$ 125,089
Payment for business acquisitions, net of cash acquired	124,149
Cash and cash equivalents	$ 1,605
Acquired intangible assets, weighted average amortization period	7 years
Goodwill	$ 105,114
Acquisition related cost	881
Acquired assets	13,836
Liabilities assumed	9,654
Recognized net deferred tax asset	1,094
Rage Frameworks Inc \| Customer-Related Intangible Assets
Business Acquisition [Line Items]
Intangible assets	1,600
Rage Frameworks Inc \| Marketing-Related Intangible Assets
Business Acquisition [Line Items]
Intangible assets	600
Rage Frameworks Inc \| Technology-related intangible assets
Business Acquisition [Line Items]
Intangible assets	12,400
Rage Frameworks Inc \| Other Intangible Assets
Business Acquisition [Line Items]
Intangible assets	$ 100

Business Acquisitions - Other Acquisitions in 2017 - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Jan. 08, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Payment for business acquisitions, net of cash acquired		$ 284,822	$ 45,162	$ 21,363
Goodwill		1,337,122	$ 1,069,408	$ 1,038,346
Acquisition related cost	$ 164
Acquired assets	412
Liabilities assumed	$ 617
Other Acquisitions
Business Acquisition [Line Items]
Business combination estimated purchase consideration		87,586
Payment for business acquisitions, net of cash acquired		76,612
Cash and cash equivalents		$ 254
Acquired intangible assets, weighted average amortization period		5 years
Goodwill		$ 56,521
Acquisition related cost		2,369
Acquired assets		10,387
Liabilities assumed		11,239
Recognized net deferred tax asset		6,570
Other Acquisitions \| Customer-Related Intangible Assets
Business Acquisition [Line Items]
Intangible assets		33,494
Other Acquisitions \| Marketing-Related Intangible Assets
Business Acquisition [Line Items]
Intangible assets		1,936
Other Acquisitions \| Technology-related intangible assets
Business Acquisition [Line Items]
Intangible assets		2,956
Other Acquisitions \| Other Intangible Assets
Business Acquisition [Line Items]
Intangible assets		100
Kraft Foods Group Brands LLC
Business Acquisition [Line Items]
Contingent earn-out consideration-Low end		0
Contingent earn-out consideration-High end		10,000
LeaseDimensions Inc.
Business Acquisition [Line Items]
Contingent earn-out consideration-Low end		0
Contingent earn-out consideration-High end		$ 3,000

Business Acquisitions - Summary of Acquisition Date, Goodwill Reporting Unit and Tax Deductibility of Goodwill of Each Acquisition (Detail)	12 Months Ended
	Dec. 31, 2017
Kraft Foods Group Brands LLC
Business Acquisition [Line Items]
Acquisition date	Oct. 16, 2017
Goodwill reporting unit	India
Tax deductibility of goodwill	Deductible
Onsource L L C
Business Acquisition [Line Items]
Acquisition date	Jul. 18, 2017
Goodwill reporting unit	India
Tax deductibility of goodwill	Deductible
I T Business Of Birlasoft
Business Acquisition [Line Items]
Acquisition date	Jul. 18, 2017
Goodwill reporting unit	IT Services
Tax deductibility of goodwill	Deductible
Image Processing Business Of Fiserv Solutions Of Australia Pty Ltd
Business Acquisition [Line Items]
Acquisition date	May 11, 2017
Goodwill reporting unit	India
Tax deductibility of goodwill	Non-deductible
LeaseDimensions Inc.
Business Acquisition [Line Items]
Acquisition date	Feb. 15, 2017
Goodwill reporting unit	Americas
Tax deductibility of goodwill	Non-deductible

Business Acquisitions - Endeavour Software Technologies Private Limited - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Apr. 13, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 08, 2016
Business Acquisition [Line Items]
Payment for business acquisitions, net of cash acquired		$ 284,822	$ 45,162	$ 21,363
Goodwill		$ 1,337,122	$ 1,069,408	$ 1,038,346
Acquired assets					$ 412
Liabilities assumed					$ 617
Endeavour Software Technologies Private Limited
Business Acquisition [Line Items]
Date of acquisition	Apr. 13, 2016
Ownership percentage acquired	100.00%
Purchase consideration	$ 14,788
Payment for business acquisitions, net of cash acquired	10,345
Cash and cash equivalents	2,373
Contingent earn-out consideration-Low end	0
Contingent earn-out consideration-High end	$ 3,500
Acquired intangible assets, weighted average amortization period	3 years
Goodwill	$ 8,936
Acquired assets	5,854
Liabilities assumed	1,735
Endeavour Software Technologies Private Limited \| Customer-Related Intangible Assets
Business Acquisition [Line Items]
Intangible assets	800
Endeavour Software Technologies Private Limited \| Marketing-Related Intangible Assets
Business Acquisition [Line Items]
Intangible assets	900
Endeavour Software Technologies Private Limited \| Other Intangible Assets
Business Acquisition [Line Items]
Intangible assets	$ 950

Business Acquisitions - Strategic Sourcing Excellence Limited - Additional Information (Detail) - USD ($)		2 Months Ended
	Jan. 08, 2016	Apr. 30, 2018	Jan. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Acquisition related cost	$ 164,000
Acquired assets	412,000
Liabilities assumed	$ 617,000
Goodwill				$ 1,337,122,000	$ 1,069,408,000	$ 1,038,346,000
Strategic Sourcing Excellence LLC
Business Acquisition [Line Items]
Date of acquisition	Jan. 08, 2016
Ownership percentage acquired	51.00%
Preliminary estimated purchase consideration	$ 14,541,000
Cash consideration to acquired certain assets and assumed certain liabilities	2,550,000
Contingent earn-out consideration-High end	$ 20,000,000
Equity method investment ownership percentage	49.00%
Goodwill	$ 14,445,000
Strategic Sourcing Excellence LLC \| Customer Relationships
Business Acquisition [Line Items]
Intangible assets	$ 300,000
Acquired intangible assets, weighted average amortization period	5 years
Put Or Call Option \| Strategic Sourcing Excellence LLC
Business Acquisition [Line Items]
Contingent earn-out consideration-High end	$ 9,800,000
Call Option \| Strategic Sourcing Excellence LLC \| Subsequent Event
Business Acquisition [Line Items]
Equity method investment ownership percentage			49.00%
Put Option \| Strategic Sourcing Excellence LLC \| Scenario, Forecast
Business Acquisition [Line Items]
Equity method investment ownership percentage		49.00%
Put Option \| Strategic Sourcing Excellence LLC \| Minimum \| Scenario, Forecast
Business Acquisition [Line Items]
Selling equity holders put option exercise price		$ 2,450,000
Put Option \| Strategic Sourcing Excellence LLC \| Maximum \| Scenario, Forecast
Business Acquisition [Line Items]
Selling equity holders put option exercise price		$ 2,950,000

Business Acquisitions - PNMSoft Ltd. - Additional Information (Detail) - USD ($) $ in Thousands			12 Months Ended
	Aug. 04, 2016	Jan. 08, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Payment for business acquisitions, net of cash acquired			$ 284,822	$ 45,162	$ 21,363
Goodwill			$ 1,337,122	$ 1,069,408	$ 1,038,346
Acquisition related cost		$ 164
Acquired assets		412
Liabilities assumed		$ 617
PNMSoft Ltd
Business Acquisition [Line Items]
Date of acquisition	Aug. 04, 2016
Percentage of equity interest acquired	100.00%
Purchase consideration	$ 35,341
Payment for business acquisitions, net of cash acquired	28,128
Cash and cash equivalents	2,853
Contingent earn-out consideration-Low end	0
Contingent earn-out consideration-High end	$ 9,000
Acquired intangible assets, weighted average amortization period	2 years
Goodwill	$ 25,101
Acquisition related cost	1,273
Acquired assets	7,110
Liabilities assumed	4,366
Recognized net deferred tax liability	944
PNMSoft Ltd \| Customer-Related Intangible Assets
Business Acquisition [Line Items]
Intangible assets	1,700
PNMSoft Ltd \| Marketing-Related Intangible Assets
Business Acquisition [Line Items]
Intangible assets	1,630
PNMSoft Ltd \| Other Intangible Assets
Business Acquisition [Line Items]
Intangible assets	$ 5,110

Business Acquisitions - IT Support Business - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Nov. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Gain (loss) on divestiture		$ (5,668)	$ 5,214
IT Support Business \| Europe
Business Acquisition [Line Items]
Sale proceeds	$ 0
Net revenues		4,546
Net profit (loss)		$ (9,706)
Gain (loss) on divestiture	$ (5,668)

Summary of Calculation of Gain (Loss) on Sale of Business (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Nov. 30, 2017	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net sale proceeds			$ (4,738)	$ 17,242
(Loss) Gain on divestiture included in other income (expense), net			$ (5,668)	$ 5,214
IT Support Business \| Europe
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net assets of the business, including intangible assets, allocated goodwill and the translation impact thereof	$ 5,569
Selling expenses	99
(Loss) Gain on divestiture included in other income (expense), net	$ (5,668)
Atyati Technologies Private Limited
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net sale proceeds		$ 17,155
Net assets of the business, including intangible assets, allocated goodwill and the translation impact thereof		11,941
Selling expenses		427
(Loss) Gain on divestiture included in other income (expense), net		$ 5,214

Business Acquisitions - Atyati Technologies Private Limited - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Proceeds from divestiture of business, net of cash divested		$ (4,738)	$ 17,242
Gain (loss) on divestiture		$ (5,668)	5,214
Atyati Technologies Private Limited
Business Acquisition [Line Items]
Proceeds from divestiture of business, net of cash divested	$ 17,155
Net of selling expenses	427
Cash divested	854
Net revenues			14,958
Net profit (loss)			$ 64
Gain (loss) on divestiture	$ 5,214

Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash And Cash Equivalents [Abstract]
Cash and other bank balances	$ 504,468	$ 422,623
Total	$ 504,468	$ 422,623	$ 450,907	$ 461,788

Reserve for Doubtful Receivables (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Receivables [Abstract]
Opening Balance	$ 15,519	$ 11,530	$ 15,192
Additions due to acquisitions	235
Additions charged to cost and expense	9,819	7,282	2,449
Deductions/effect of exchange rate fluctuations	(1,913)	(3,293)	(6,111)
Closing balance	$ 23,660	$ 15,519	$ 11,530

Accounts Receivable, Net of Reserve for Doubtful Receivables - Additional Information (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Receivables [Abstract]
Gross accounts receivable	$ 716,745,000	$ 630,784,000
Reserve for doubtful receivables	23,660,000	15,519,000	$ 11,530,000	$ 15,192,000
Net accounts receivable	693,085,000	615,265,000
Accounts receivable due after one year	1,624,000	3,272,000
Accounts receivable from related parties	36,000	2,490,000
Reserve for doubtful receivables from related parties	$ 0	$ 0

Fair Value of Assets and Liabilities Measured on Recurring Basis, Including Derivative Instruments (Detail) - Fair Value, Measurements, Recurring - USD ($)
$ in Thousands

Dec. 31, 2017

Dec. 31, 2016

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Derivative instrument, asset

^[1],[2]

$ 73,098

$ 55,386

Total, assets

73,098

55,386

Earnout Consideration

^[3],[4]

24,732

22,435

Derivative instrument, liability

^[2],[3]

18,188

17,353

Total, liabilities

42,920

39,788

Redeemable non-controlling interest

^[5]

4,750

4,520

Fair Value, Inputs, Level 2

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Derivative instrument, asset

^[1],[2]

73,098

55,386

Total, assets

73,098

55,386

Derivative instrument, liability

^[2],[3]

18,188

17,353

Total, liabilities

18,188

17,353

Fair Value, Inputs, Level 3

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Earnout Consideration

^[3],[4]

24,732

22,435

Total, liabilities

24,732

22,435

Redeemable non-controlling interest

^[5]

$ 4,750

$ 4,520

[1]	Included in prepaid expenses and other current assets and other assets in the consolidated balance sheets.
[2]	The Company values its derivative instruments based on market observable inputs, including both forward and spot prices for the relevant currencies and interest rate indices for relevant interest rates. The quotes are taken from an independent market database
[3]	Included in accrued expenses and other current liabilities and other liabilities in the consolidated balance sheets.
[4]	The fair value of earn-out consideration, calculated as the present value of expected future payments to be made to the sellers of acquired businesses, was derived by estimating the future financial performance of the acquired businesses using the earn-out formula and performance targets specified in each purchase agreement and adjusting the result to reflect the Company’s estimate of the likelihood of achievement of such targets. Given the significance of the unobservable inputs, the valuations are classified in level 3 of the fair value hierarchy.
[5]	The Company’s estimate of the fair value of redeemable non-controlling interest as of December 31, 2017 is based on unobservable inputs considering the assumptions that market participants would make in pricing the obligation. Given the significance of the unobservable inputs, the valuation was classified in level 3 of the fair value hierarchy. Refer to Note 3—Business Acquisitions.

Fair Value of Earn-out Consideration (Detail) - Fair Value, Inputs, Level 3 - Business Acquisition Contingent Consideration - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]

Opening balance

$ 22,435

$ 22,820

Earn-out consideration payable in connection with acquisitions

10,720

14,550

Payments made of earn-out consideration

(7,239)

(1,611)

Change in fair value

^[1]

(3,695)

(14,869)

Other

^[2]

2,511

1,545

Ending balance

$ 24,732

$ 22,435

[1]	Changes in the fair value of earn-out consideration are reported in other operating (income) expense, net in the consolidated statements of income.
[2]	Interest expense is included in interest income (expense), net and the impact of changes in foreign exchange is reported in foreign exchange gains (losses), net in the consolidated statements of income. The cumulative translation adjustment is reported as a component of other comprehensive income (loss).

Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Amount of gain (loss) recognized in income on ineffective portion of derivatives and amount excluded from effectiveness testing	$ 0	$ 0	$ 0
Forward Foreign Exchange Contracts \| Maximum
Derivative [Line Items]
Derivative financial instrument contracts, maturity period	60 months
Interest Rate Swaps \| Maximum
Derivative [Line Items]
Derivative financial instrument contracts, maturity period	60 months

Aggregate Notional Principal Amounts of Outstanding Derivative Financial Instruments with Related Balance Sheet Exposure (Detail) - USD ($)

Dec. 31, 2017

Dec. 31, 2016

Derivative financial instrument, balance sheet exposure asset (liability)

^[1]

$ 54,910,000

$ 38,034,000

United States Dollars (sell) Indian Rupees (buy)

Derivative financial instrument, balance sheet exposure asset (liability)

^[2]

1,289,400,000

1,108,400,000

^[1]

54,398,000

6,669,000

United States Dollars (sell) Mexican Peso (buy)

Derivative financial instrument, balance sheet exposure asset (liability)

^[2]

9,000,000

9,120,000

^[1]

(441,000)

(187,000)

United States Dollars (sell) Philippines Peso (buy)

Derivative financial instrument, balance sheet exposure asset (liability)

^[2]

76,650,000

70,050,000

^[1]

69,000

(1,036,000)

Euro (sell) United States Dollars (buy)

Derivative financial instrument, balance sheet exposure asset (liability)

^[2]

170,542,000

138,613,000

^[1]

(2,069,000)

9,180,000

Pound Sterling (buy) United States Dollars (sell)

Derivative financial instrument, balance sheet exposure asset (liability)

^[2]

24,041,000

^[1]

253,000

Euro (sell) Romanian Leu (buy)

Derivative financial instrument, balance sheet exposure asset (liability)

^[2]

35,826,000

29,805,000

^[1]

(892,000)

(152,000)

Japanese Yen (sell) Chinese Renminbi (buy)

Derivative financial instrument, balance sheet exposure asset (liability)

^[2]

60,768,000

77,267,000

^[1]

1,918,000

(742,000)

Pound Sterling (sell) United States Dollars (buy)

Derivative financial instrument, balance sheet exposure asset (liability)

^[2]

80,871,000

104,142,000

^[1]

(2,478,000)

14,228,000

Australian Dollars (sell) United States Dollars (buy)

Derivative financial instrument, balance sheet exposure asset (liability)

^[2]

136,092,000

114,412,000

^[1]

(5,180,000)

2,328,000

Interest Rate Swap Floating To Fixed [Member]

Derivative financial instrument, balance sheet exposure asset (liability)

^[2]

432,117,000

456,810,000

^[1]

$ 9,332,000

$ 7,746,000

[1]	Balance sheet exposure is denominated in U.S. dollars and denotes the mark-to-market impact of the derivative financial instruments on the reporting date.
[2]	Notional amounts are key elements of derivative financial instrument agreements but do not represent the amount exchanged by counterparties and do not measure the Company’s exposure to credit, foreign exchange, interest rate or other market risks. However, the amounts exchanged are based on the notional amounts and other provisions of the underlying derivative financial instrument agreements.

Fair Values of Derivative Instruments and Location in Financial Statements (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Prepaid Expenses and Other Current Assets \| Not Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Fair value of assets	$ 4,635	$ 809
Accrued Expenses and Other Current Liabilities \| Not Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Fair value of liabilities	254	237
Cash Flow Hedges \| Prepaid Expenses and Other Current Assets
Derivatives Fair Value [Line Items]
Fair value of assets	43,557	33,921
Cash Flow Hedges \| Other Assets
Derivatives Fair Value [Line Items]
Fair value of assets	24,906	20,657
Cash Flow Hedges \| Accrued Expenses and Other Current Liabilities
Derivatives Fair Value [Line Items]
Fair value of liabilities	10,092	4,540
Cash Flow Hedges \| Other Liabilities
Derivatives Fair Value [Line Items]
Fair value of liabilities	$ 7,842	$ 12,576

Cash Flow Hedges, Gains (Losses) Recorded as Component of Other Comprehensive Income (Loss) or Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Opening balance, before-tax amount	$ 37,461	$ (30,090)	$ (66,786)
Net gains (losses) reclassified into statement of income upon completion of hedged transactions, before-tax amount	54,494	(6,799)	(42,106)
Changes in fair value of effective portion of outstanding derivatives, net, before-tax amount	67,562	60,752	(5,410)
Gain (loss) on cash flow hedging derivatives, net, before-tax amount	13,068	67,551	36,696
Closing balance, before-tax amount	50,529	37,461	(30,090)
Opening balance, tax (expense) or benefit	(13,979)	9,830	23,646
Net gains (losses) reclassified into statement of income upon completion of hedged transactions, tax (expense) or benefit	(17,725)	409	15,346
Changes in fair value of effective portion of outstanding derivatives, net, tax (expense) or benefit	(18,182)	(23,400)	1,530
Gain (loss) on cash flow hedging derivatives, net, tax (expense) or benefit	(457)	(23,809)	(13,816)
Closing balance, tax (expense) or benefit	(14,436)	(13,979)	9,830
Opening balance, net of tax amount	23,482	(20,260)	(43,140)
Net gains (losses) reclassified into statement of income upon completion of hedged transactions, net of tax amount	36,769	(6,390)	(26,760)
Changes in fair value of effective portion of outstanding derivatives, net, net of tax amount	49,380	37,352	(3,880)
Gain (loss) on cash flow hedging derivatives, net of taxes amount	12,611	43,742	22,880
Closing balance, net of tax amount	$ 36,093	$ 23,482	$ (20,260)

Gains or Losses Recorded as Component of Other Comprehensive Income (Loss) or Other Comprehensive Income (Detail) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Amount of Gain (loss) recognized in OCI on Derivatives (Effective Portion)

$ 67,562

$ 60,752

$ (5,410)

Amount of Gain (loss) reclassified from OCI into Statement of Income (Effective Portion)

54,494

(6,799)

(42,106)

Non designated Hedges, amount of (Gain) Loss recognized in Statement of Income on Derivatives

16,696

2,921

6,566

Net revenues

Amount of Gain (loss) reclassified from OCI into Statement of Income (Effective Portion)

5,858

12,859

13,667

Cost of Revenue

Amount of Gain (loss) reclassified from OCI into Statement of Income (Effective Portion)

37,849

(14,223)

(44,634)

Selling, General and Administrative Expenses

Amount of Gain (loss) reclassified from OCI into Statement of Income (Effective Portion)

10,849

(3,765)

(11,139)

Interest Expense

Amount of Gain (loss) reclassified from OCI into Statement of Income (Effective Portion)

(62)

(1,670)

Forward Foreign Exchange Contracts

Amount of Gain (loss) recognized in OCI on Derivatives (Effective Portion)

66,037

54,664

(5,410)

Forward Foreign Exchange Contracts | Foreign Exchange (Gains) Losses, Net

Non designated Hedges, amount of (Gain) Loss recognized in Statement of Income on Derivatives

^[1]

16,696

2,921

$ 6,566

Interest Rate Swaps

Amount of Gain (loss) recognized in OCI on Derivatives (Effective Portion)

$ 1,525

$ 6,088

[1]

Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Prepaid Expense And Other Assets Current [Abstract]
Advance income and non-income taxes	$ 51,832	$ 50,676
Deferred transition costs	62,029	45,252
Derivative instruments	48,192	34,730
Prepaid expenses	16,944	22,222
Customer acquisition cost	19,327	11,126
Employee advances	5,014	6,880
Deposits	4,719	2,688
Advances to suppliers	2,705	10,059
Others	25,580	5,516
Prepaid expenses and other current assets, net	$ 236,342	$ 189,149

Property, Plant and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 666,031	$ 600,554
Less: accumulated depreciation, amortization and impairment	(459,001)	(407,336)
Property, plant and equipment, net	207,030	193,218
Land
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	10,209	9,635
Buildings
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	46,007	44,487
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	43,091	37,421
Computer Equipment and Servers
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	210,725	187,119
Plant, Machinery and Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	92,981	84,677
Computer Software
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	137,459	119,648
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	102,072	92,313
Vehicles
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	6,418	6,753
Capital Work in Progress
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 17,069	$ 18,501

Property, Plant and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property Plant And Equipment [Line Items]
Depreciation and amortization	$ 58,503	$ 54,553	$ 54,286
Property, plant and equipment held under capital lease arrangements, gross	3,302	3,183
Tangible assets write-down	8,000
Technology Related Intangible Assets
Property Plant And Equipment [Line Items]
Tangible assets write-down	2,240
Software Amortization
Property Plant And Equipment [Line Items]
Depreciation and amortization	11,400	9,471	9,114
Effect of Reclassification of Foreign Exchange (Gains) Losses
Property Plant And Equipment [Line Items]
Depreciation and amortization	(1,727)	744	2,501
Assets Held Under Capital Leases
Property Plant And Equipment [Line Items]
Depreciation and amortization	1,682	1,564	1,594
Depreciation Expense on Property, Plant And Equipment
Property Plant And Equipment [Line Items]
Depreciation and amortization	44,909	$ 45,826	$ 47,673
Computer Software
Property Plant And Equipment [Line Items]
Tangible assets write-down	$ 5,760

Changes in Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
Changes in Goodwill (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Opening balance	$ 1,069,408	$ 1,038,346
Goodwill relating to acquisitions consummated during the period	229,745	51,535
Goodwill relating to divestitures during the period		(2,226)
Impact of measurement period adjustments	(106)	(59)
Effect of exchange rate fluctuations	38,075	(18,188)
Closing balance	$ 1,337,122	$ 1,069,408

Goodwill Allocated to Reporting Units (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Line Items]
Goodwill	$ 1,337,122	$ 1,069,408	$ 1,038,346
India
Goodwill [Line Items]
Goodwill	735,596	493,084
China
Goodwill [Line Items]
Goodwill	60,171	58,139
Europe
Goodwill [Line Items]
Goodwill	41,775	36,584
Americas
Goodwill [Line Items]
Goodwill	57,021	48,713
IT Services
Goodwill [Line Items]
Goodwill	$ 442,559	$ 432,888

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill deductible for tax purposes	$ 120,617,000	$ 39,032,000
Amortization of acquired intangible assets	36,412,000	27,183,000	$ 28,513,000
Technology-related intangible assets
Goodwill and Intangible Assets Disclosure [Line Items]
Amortization of acquired intangible assets	467,000	0	$ 0
Customer-Related Intangible Assets
Goodwill and Intangible Assets Disclosure [Line Items]
Intangible assets write-down	$ 1,311,000	871,000
Intangible Software Asset
Goodwill and Intangible Assets Disclosure [Line Items]
Intangible assets write-down		10,324,000
IT Services
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill impairment		$ 0

Intangible Assets Acquired Either Individually or with Group of Other Assets or in Business Combination (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Acquired Finite Lived Intangible Assets [Line Items]
Gross carrying amount	$ 494,423	$ 393,027
Accumulated amortization & Impairment	362,833	314,081
Net	131,590	78,946
Customer-Related Intangible Assets
Acquired Finite Lived Intangible Assets [Line Items]
Gross carrying amount	369,173	312,041
Accumulated amortization & Impairment	293,029	260,018
Net	76,144	52,023
Marketing-Related Intangible Assets
Acquired Finite Lived Intangible Assets [Line Items]
Gross carrying amount	52,443	45,098
Accumulated amortization & Impairment	39,212	30,571
Net	13,231	14,527
Technology-related intangible assets
Acquired Finite Lived Intangible Assets [Line Items]
Gross carrying amount	54,189	26,116
Accumulated amortization & Impairment	28,278	21,026
Net	25,911	5,090
Other Intangible Assets
Acquired Finite Lived Intangible Assets [Line Items]
Gross carrying amount	3,081	2,875
Accumulated amortization & Impairment	2,314	2,466
Net	767	409
Intangible Assets Under Development [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Gross carrying amount	15,537	6,897
Net	$ 15,537	$ 6,897

Estimated Amortization Schedule of Intangible Assets for Future Periods (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
2018	$ 38,569
2019	27,518
2020	26,831
2021	13,080
2022 and beyond	25,592
Net	$ 131,590	$ 78,946

Other Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Assets Noncurrent Disclosure [Abstract]
Customer acquisition cost	$ 37,017	$ 30,996
Advance income and non-income taxes	63,474	60,203
Deferred transition costs	77,255	74,462
Deposits	32,174	29,853
Derivative instruments	24,906	20,657
Prepaid expenses	2,849	3,179
Accounts receivable due after one year	1,624	3,272
Others	22,870	19,706
Other assets	$ 262,169	$ 242,328

Future Minimum Lease Payments under Operating Lease Arrangements (Detail) $ in Thousands	Dec. 31, 2017 USD ($)
Leases [Abstract]
2018	$ 59,269
2019	54,844
2020	47,788
2021	43,692
2022	38,275
2023 and beyond	122,150
Total minimum lease payments	$ 366,018

Leases - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Leases [Abstract]
Rent expenses	$ 59,484	$ 50,827	$ 50,342
Rental expense including effect of reclassification of foreign exchange (gains) losses	$ (1,533)	$ 598	$ 2,037

Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accrued Liabilities And Other Liabilities [Abstract]
Accrued expenses	$ 204,997	$ 163,400
Accrued employee cost	204,506	179,360
Deferred transition revenue	52,233	50,552
Statutory liabilities	36,283	36,878
Retirement benefits	21,074	17,616
Derivative instruments	10,346	4,777
Advance from customers	25,476	21,969
Earn-out consideration	14,928	6,885
Other liabilities	13,093	15,461
Capital lease obligations	1,546	1,349
Accrued expenses and other current liabilities, net	$ 584,482	$ 498,247

Long-Term Debt - Additional Information (Detail)	1 Months Ended		12 Months Ended
Long-Term Debt - Additional Information (Detail)	Mar. 31, 2017 USD ($) Day	Jun. 30, 2015 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Aug. 30, 2012 USD ($)
Debt Instrument [Line Items]
Extinguishment of outstanding term loan		$ 663,188,000
Acceleration amortization of debt issuance cost		$ 10,050,000
Margin over LIBOR		1.50%	1.50%	1.50%
Debt discount and underwriting fee			$ 2,630,000		$ 6,584,000
New Credit Facility
Debt Instrument [Line Items]
Margin over LIBOR		1.50%
Credit facility, base rate		0.50%
3.70% Senior Notes
Debt Instrument [Line Items]
Debt amount outstanding			347,761,000
Debt amortization expense			$ 2,239,000
Principal amount of senior notes issued	$ 350,000,000
Interest rate on senior notes	3.70%
Net proceeds from issue of senior notes	$ 348,519,000
Debt discount and underwriting fee	1,481,000
Other debt issuance costs	1,161,000
Total debt issuance cost	$ 2,642,000
Debt instrument, maturity date			Apr. 01, 2022
Debt instrument description			The Company will pay interest on the notes semi-annually in arrears on April 1 and October 1 of each year, ending on the maturity date of April 1, 2022.
Debt instrument redemption price percentage	100.00%
Debt instrument redemption date			Mar. 01, 2022
Debt repurchase price as percentage of aggregate principal value upon certain change of controls	101.00%
Maximum increase in downgrade of credit rating of notes to adjust interest rate payable	2.00%
Debt instrument, percentage increase in interest payable on notes if exchange offer fails during first 90 days	0.25%
Debt instrument, number of days to provide offer to exchange notes for registered notes \| Day	455
Debt instrument, percentage increase in interest payable on notes if exchange offer fails, after first 90 days	0.25%
Debt instrument, percentage increase in interest payable on notes if exchange offer fails, maximum	0.50%
Term Loan Credit Facility
Debt Instrument [Line Items]
Debt amount outstanding			$ 698,152,000	$ 737,333,000
Debt amortization expense			1,848,000	$ 2,667,000
Principal amount of term loan			$ 10,000,000
Credit facility, frequency of payments			Quarterly
Maturity date of term loan agreement			Jun. 30, 2020
Term Loan Credit Facility \| New Credit Facility
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity		$ 800,000,000
Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity			$ 350,000,000			$ 250,000,000
Acceleration amortization of debt issuance cost		65,000
Revolving Credit Facility \| New Credit Facility
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity		$ 350,000,000

Maturity Profile of Term Loan Net of Debt Amortization Expense (Detail) - Term Loan Credit Facility - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
2018	$ 39,226
2019	39,272
2020	619,654
Total	$ 698,152	$ 737,333

Short-Term Borrowings - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Aug. 30, 2012
Line Of Credit Facility [Line Items]
Fund-based and non-fund-based credit facilities limits available		$ 15,064,000	$ 15,382,000
Utilization of credit facility for non fund-based usage		7,900,000	10,980,000
Credit facility, amount utilized		170,978,000	160,978,000
Short-term borrowings		$ 170,000,000	$ 160,000,000
Revolving credit facility, expiration month and year		2020-06
Margin over LIBOR	1.50%	1.50%	1.50%
Percentage of commitment fee		0.25%	0.25%
Line of credit covenant condition		The credit agreement contains certain customary covenants, including a maximum leverage covenant and a minimum interest coverage ratio.
Revolving Credit Facility
Line Of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity		$ 350,000,000		$ 250,000,000
Non-Fund-Based Credit Facility
Line Of Credit Facility [Line Items]
Credit facility, amount utilized		$ 978,000	$ 978,000
Fund-Based Credit Facility
Line Of Credit Facility [Line Items]
Margin over LIBOR		1.50%	1.50%

Other Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Liabilities Disclosure [Abstract]
Accrued employee cost	$ 14,020	$ 3,976
Deferred transition revenue	70,900	72,560
Retirement benefits	40,520	39,020
Derivative instruments	7,842	12,576
Amount received from GE under indemnification arrangement, pending adjustment	3,359	3,159
Advance from customers	790	2,371
Earn-out consideration	9,804	15,550
Others	18,710	11,078
Capital lease obligations	2,664	2,500
Other Liabilities	$ 168,609	$ 162,790

Funded Status of Defined Benefit Plans and Amount Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Compensation And Retirement Disclosure [Abstract]
Projected benefit obligation at the beginning of the year	$ 45,283	$ 35,617
Service cost	7,735	5,661	$ 5,578
Actuarial loss	4,493	6,749
Interest cost	3,252	2,585	2,629
Liabilities assumed on acquisition		693
Benefits paid	(5,367)	(4,967)
Special termination benefit	57
Effect of exchange rate changes	2,641	(1,055)
Projected benefit obligation at the end of the year	58,094	45,283	35,617
Fair value of plan assets at the beginning of the year	30,871	28,549
Employer contributions	15,176	5,776
Actual gain on plan assets	2,746	1,777
Assets assumed on acquisition	0	170
Actuarial gain	11
Benefits paid	(5,301)	(4,897)
Effect of exchange rate changes	2,057	(504)
Fair value of plan assets at the end of the year	$ 45,560	$ 30,871	$ 28,549

Amounts Included in Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Compensation And Retirement Disclosure [Abstract]
Net actuarial loss	$ (12,228)	$ (8,979)
Deferred tax assets	2,221	2,759
Other comprehensive income, net	$ (10,007)	$ (6,220)

Changes in Other Comprehensive Income (Loss) (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Compensation And Retirement Disclosure [Abstract]
Net actuarial loss	$ (4,182)
Amortization of net actuarial loss	1,177
Deferred income taxes	(670)
One-time cost	211
Effect of exchange rate changes	(323)
Other comprehensive income (loss), net	$ (3,787)

Net Defined Benefit Plan Costs (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Compensation And Retirement Disclosure [Abstract]
Service costs	$ 7,735	$ 5,661	$ 5,578
Interest costs	3,252	2,585	2,629
Amortization of actuarial loss	1,177	(113)	330
Expected return on plan assets	(2,412)	(2,043)	(2,154)
One-time cost	209
Special termination benefits	426
Net defined benefit plan costs	$ 10,387	$ 6,090	$ 6,383

Employee Benefit Plans - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Amount in other comprehensive loss expected to be recognized as component of net periodic benefit cost over next fiscal year	$ 1,353
Benefit Obligations Of Philippines Plan \| Minimum
Defined Benefit Plan Disclosure [Line Items]
Expectation of the average long term rate of return expected, years	15 years
Benefit Obligations Of Philippines Plan \| Maximum
Defined Benefit Plan Disclosure [Line Items]
Expectation of the average long term rate of return expected, years	20 years

Weighted Average Assumptions used to Determine Benefit Obligations, Gratuity Plan (Detail) - Benefit Obligations Of Gratuity Plan	Dec. 31, 2017	Dec. 31, 2016
Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	7.40%	7.10%
Rate of increase in compensation per annum	5.20%	5.20%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	7.60%	7.50%
Rate of increase in compensation per annum	11.00%	11.00%

Weighted Average Assumptions used to Determine Plan Costs, Gratuity Plan (Detail) - Gratuity Plan Costs	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets per annum	7.50%	7.50%	8.50%
Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	7.10%	8.30%	8.50%
Rate of increase in compensation per annum	5.20%	5.20%	5.20%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	7.50%	8.45%	8.55%
Rate of increase in compensation per annum	11.00%	11.00%	11.00%

Weighted Average Assumptions used to Determine Benefit Obligations, Mexican Plan (Detail) - Benefit Obligations Of Mexican Plan	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Discount rate	7.60%	6.80%
Rate of increase in compensation per annum	5.50%	5.50%

Weighted Average Assumptions used to Determine Plan Costs, Mexican Plan (Detail) - Mexican Plan Costs	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Discount rate	6.80%	6.50%	6.50%
Rate of increase in compensation per annum	5.50%	5.50%	5.50%
Expected long-term rate of return on plan assets per annum	0.00%	0.00%	0.00%

Weighted Average Assumptions used to Determine Benefit Obligations, Japan Plan (Detail) - Benefit Obligations Of Japan Plan	Dec. 31, 2017	Dec. 31, 2016
Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	0.113%	0.08%
Rate of increase in compensation per annum	0.00%	0.00%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	0.789%	1.30%
Rate of increase in compensation per annum	3.55%	3.55%

Weighted Average Assumptions used to Determine Plan Costs, Japan Plan (Detail) - Japan Plan Costs	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	0.08%	0.24%	0.20%
Rate of increase in compensation per annum	0.00%	0.00%	0.00%
Expected long-term rate of return on plan assets per annum	0.00%	0.00%	2.69%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	1.30%	1.30%	1.30%
Rate of increase in compensation per annum	3.55%	3.55%	3.55%
Expected long-term rate of return on plan assets per annum	3.09%	3.77%	3.44%

Fair Value of Plan Assets (Detail) - USD ($)
$ in Thousands

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Fair Value, Inputs, Level 1

$ 45,560

$ 30,871

$ 28,549

Fair Value, Inputs, Level 2

6,328

10,001

39,232

20,870

Cash

Cash | Fair Value, Inputs, Level 1

472

4,809

472

4,809

Fixed Income Securities

Fixed Income Securities | Fair Value, Inputs, Level 1

^[1]

42,328

23,659

Fixed Income Securities | Fair Value, Inputs, Level 2

^[1]

3,419

3,001

^[1]

38,909

20,658

Other Securities

Other Securities | Fair Value, Inputs, Level 1

^[2]

2,760

2,403

Other Securities | Fair Value, Inputs, Level 2

^[2]

2,437

2,191

Outstanding, shares arising out of options, beginning balance

^[2]

$ 323

$ 212

[1]	Includes investments in funds that invest 100% of their assets in fixed income securities such as money market instruments, government securities and public and private bonds
[2]	Includes investments in funds that invest primarily in fixed income securities and the remaining portion in equity securities.

Fair Value of Plan Assets (Parenthetical) (Detail)	12 Months Ended
Fair Value of Plan Assets (Parenthetical) (Detail)	Dec. 31, 2017	Dec. 31, 2016
Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of investment in funds	100.00%	100.00%

Expected Benefit Plan Payments Reflecting Expected Future Service (Detail) $ in Thousands	Dec. 31, 2017 USD ($)
Compensation And Retirement Disclosure [Abstract]
2018	$ 8,469
2019	8,823
2020	9,330
2021	9,946
2022	10,118
2023 - 2027	48,107
Defined benefit plan expected future benefit payments	$ 94,793

Amounts Contributed to Defined Contribution Plans in Various Jurisdictions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plans, contributed amount	$ 61,221	$ 56,242	$ 47,717
India
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plans, contributed amount	22,242	19,074	15,915
U.S.
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plans, contributed amount	11,147	10,379	8,148
U.K.
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plans, contributed amount	7,823	6,593	4,453
China
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plans, contributed amount	15,950	15,512	14,511
Other Regions
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plans, contributed amount	$ 4,059	$ 4,684	$ 4,690

Stock-Based Compensation - Additional Information (Detail) - USD ($)						1 Months Ended	3 Months Ended				12 Months Ended
	Dec. 20, 2017	Sep. 21, 2017	Jun. 28, 2017	Mar. 28, 2017	Apr. 11, 2012	Jan. 31, 2015	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	May 09, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation cost											$ 35,112,000	$ 24,686,000	$ 24,684,000
Tax benefit recognized in relation to stock based compensation											$ 9,600,000	$ 6,446,000	6,125,000
Options granted, contractual period, years											10 years
Cash dividend paid per share	$ 0.06	$ 0.06	$ 0.06	$ 0.06			$ 0.06	$ 0.06	$ 0.06	$ 0.06		$ 0
Cash received from the exercise of stock option											$ 10,772,000	$ 14,896,000	13,564,000
Cash tax benefit realized from the exercise of stock option											2,016,000	1,548,000	6,982,000
Excess tax benefit on stock-based compensation													6,560,000
Unrecognized stock-based compensation cost for options							$ 6,479,000				6,479,000
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Excess tax benefit on stock-based compensation											$ 1,723,000	$ 1,004,000	$ 6,560,000
Weighted average remaining requisite vesting period											2 years 10 months 24 days
Restricted Share Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average remaining requisite vesting period											2 years 10 months 24 days
Unrecognized stock-based compensation cost							26,543,000				$ 26,543,000
Shares to be issued on vested awards other than options											53,546	86,517		92,692	61,057
Performance Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average remaining requisite vesting period											2 years
Unrecognized stock-based compensation cost							$ 28,992,000				$ 28,992,000
Performance Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Minimum statutory withholding taxes, Shares						845,524
Performance Units \| January, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares to be issued on vested awards other than options														1,329,270
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of fair value per share allowed to eligible employees to purchase through payroll deductions											90.00%
Maximum percentage of employee's base salary allowed to be purchased							15.00%				15.00%
Maximum dollar amount of common shares allowed to be purchased											$ 25,000
Common shares reserved for issuance							4,200,000				4,200,000
Issuance of common shares under the employee stock purchase plan (in shares)											190,435	146,685	121,485
Compensation expense for ESPP											$ 573,000	$ 428,000	$ 292,000
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award, vesting period, years											4 years
Minimum \| Restricted Share Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award, vesting period, years											3 months
Minimum \| Performance Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award, vesting period, years											6 months
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award, vesting period, years											5 years
Maximum \| Restricted Share Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award, vesting period, years											4 years
Maximum \| Performance Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award, vesting period, years											3 years
2007 Omnibus Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Amended Omnibus Plan, increase in number of common shares authorized for issuance					5,593,200											8,858,823
Number of common shares authorized for issuance					15,000,000		23,858,823				23,858,823
Genpact Limited 2017 Omnibus Incentive Compensation Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common shares authorized for issuance																	15,000,000

Significant Assumptions used in Determination of Fair Value of Options Granted (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Dividend yield	0.97%
Expected life (in months)	84 months	84 months	84 months
Risk-free rate of interest for expected life	2.25%		1.99%
Risk-free rate of interest for expected life, minimum		1.42%
Risk-free rate of interest for expected life, maximum		1.56%
Volatility	24.28%		34.97%
Volatility, minimum		25.60%
Volatility, maximum		27.22%

Summary of Stock Option Activity (Detail) - USD ($)
$ / shares in Units, $ in Thousands

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Dec. 31, 2014

Shares arising out of options

5,707,690

5,986,845

7,371,727

Granted, shares arising out of options

250,000

860,000

170,000

Forfeited, shares arising out of options

(80,000)

(145,000)

(125,000)

Expired, shares arising out of options

(1,277)

Exercised, shares arising out of options

(743,045)

(994,155)

(1,428,605)

Outstanding, shares arising out of options, ending balance

5,134,645

5,707,690

5,986,845

7,371,727

Vested and expected to vest thereafter, shares arising out of options

^[1]

4,988,875

5,457,701

5,754,969

Vested and exercisable, shares arising out of options

2,203,146

2,746,191

2,183,846

Weighted average grant-date fair value of options granted during the period

$ 6.62

$ 8.50

$ 9.15

Weighted average exercise price

Outstanding weighted average exercise price, beginning balance

18.65

16.99

15.44

Granted, weighted average exercise price

24.74

26.80

22.77

Forfeited, weighted average exercise price

20.63

17.77

19.35

Expired, weighted average exercise price

14.32

Exercised, weighted average exercise price

14.50

14.98

9.49

Outstanding weighted average exercise price, ending balance

19.52

18.65

16.99

$ 15.44

Vested and expected to vest thereafter, weighted average exercise price

^[1]

19.36

18.42

16.76

Vested and exercisable, weighted average exercise price

$ 16.17

$ 15.62

$ 12.67

Weighted average remaining contractual life (years)

Outstanding weighted average remaining contractual life (years)

5 years 7 months 6 days

5 years 9 months 18 days

5 years 10 months 24 days

Vested and expected to vest thereafter, weighted average remaining contractual life (years)

^[1]

5 years 7 months 6 days

5 years 9 months 18 days

Vested and exercisable, weighted average remaining contractual life (years)

4 years 1 month 6 days

4 years

2 years 8 months 12 days

Aggregate intrinsic value

Exercised, aggregate intrinsic value

$ 12,636

$ 9,301

$ 22,122

Outstanding aggregate intrinsic value, ending balance

62,743

34,641

48,661

Vested and expected to vest thereafter, aggregate intrinsic value

^[1]

61,779

34,150

47,325

Vested and exercisable, aggregate intrinsic value

$ 34,303

$ 23,960

$ 26,892

[1]	Options expected to vest reflect an estimated forfeiture rate.

Summary of Restricted Share Units Granted (Detail) - Restricted Share Units (RSUs) - $ / shares

1 Months Ended

12 Months Ended

Jan. 31, 2015

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Number of Restricted Share Units

Outstanding number of shares (Units), beginning balance

488,418

117,905

157,390

488,418

Granted, number of shares (Units)

1,533,836

95,553

53,546

Vested, number of shares (Units)

(45,248)

^[1]

(133,903)

^[2]

(351,338)

^[3]

Forfeited, number of shares (Units)

(1,242)

(1,135)

(33,236)

Outstanding number of shares (Units), ending balance

1,605,251

117,905

157,390

488,418

Expected to vest, number of shares (Units)

^[4]

1,371,567

107,366

147,226

Outstanding weighted average grant date fair value, beginning balance

$ 15.36

$ 20.65

$ 17.67

$ 15.36

Granted, weighted average grant date fair value

26.36

25.49

20.88

Vested, weighted average grant date fair value

18.31

^[1]

20.66

^[2]

15.29

^[3]

Forfeited, weighted average grant date fair value

25.53

14.18

14.00

Outstanding weighted average grant date fair value, ending balance

$ 26.17

$ 20.65

$ 17.67

$ 15.36

Shares to be issued on vested awards other than options

53,546

86,517

92,692

61,057

Vested in December 31, 2014

Vested RSU issued during the period

91,963

Vested in December 31, 2013

Vested RSU issued during the period

59,827

[1]	Vested RSUs were net settled by issuing 32,395 shares (net of minimum statutory tax withholding).
[2]	Vested RSUs were net settled by issuing 29,719 shares (net of minimum statutory tax withholding). 86,517 RSUs vested in the year ended December 31, 2016. 17,802 common shares underlying 34,035 of such RSUs were issued in 2017 after withholding shares to the extent of minimum statutory withholding taxes. Shares underlying the remaining 52,482 of such RSUs will be issued in 2018 after withholding shares to the extent of minimum statutory withholding taxes.
[3]	Vested RSUs were net settled by issuing 199,949 shares (net of minimum statutory tax withholding). 53,546 RSUs vested in the year ended December 31, 2015, 53,023 shares in respect of which were issued in 2017 after withholding shares to the extent of minimum statutory withholding taxes.
[4]	RSUs expected to vest reflect an estimated forfeiture rate.

Summary of Restricted Share Units Granted (Parenthetical) (Detail) - Restricted Share Units (RSUs) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
RSUs settled on vesting by issuing shares (net of minimum tax withholding)		32,395	29,719	199,949
Shares to be issued on vested awards other than options		53,546	86,517		92,692	61,057
Vested in December 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vested RSU issued during the period				53,023
Vested in December 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
RSUs settled on vesting by issuing shares (net of minimum tax withholding)		17,802
Vested RSU issued during the period		34,035
Vested in December 31, 2016 \| Scenario, Forecast
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vested RSU issued during the period	52,482

Summary of Performance Units Activity (Detail) - Performance Units - $ / shares

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Number of Performance Units

Outstanding number of shares (Units), beginning balance

3,772,128

2,499,322

1,292,750

Granted, number of shares (Units)

1,811,292

1,518,374

1,375,650

Vested, number of shares (Units)

(1,136,047)

^[1]

(855)

^[2]

Forfeited, number of shares (Units)

(1,583,913)

^[3]

(252,842)

(136,216)

Adjustment upon final determination of level of performance goal achievement

37,480

^[4]

7,274

^[5]

Adjustment due to achievement of lower than target performance

^[6]

(32,007)

Outstanding number of shares (Units), ending balance

2,900,940

3,772,128

2,499,322

Expected to vest, number of shares (Units)

^[7]

2,657,685

2,226,489

2,184,906