Derivatives and Hedge Accounting - Location of Gain or Loss Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Cost of revenues	$ 221,207	$ 170,701	$ 428,723	$ 329,522
General and administrative expenses	40,434	36,499	80,379	67,202
Selling and marketing expenses	23,985	19,724	48,155	37,959
Depreciation and amortization expense	14,075	12,310	27,677	24,411
Income before income tax expense and earnings from equity affiliates	46,828	36,878	94,094	77,803
Income tax effects on above	(11,125)	(8,865)	(22,327)	(17,823)
Net income attributable to ExlService Holdings, Inc. stockholders	35,846	28,021	72,024	59,952
Foreign exchange gain/(loss), net	1,423	1,353	3,179	1,787
Gain/ (loss) on foreign currency exchange contracts | Derivatives Designated as Hedging Instruments | Derivatives in cash flow hedging relationships | Foreign currency exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Cost of revenues	1,194	2,418	2,777	4,842
General and administrative expenses	181	294	475	546
Selling and marketing expenses	15	15	29	28
Depreciation and amortization expense	69	139	167	279
Income before income tax expense and earnings from equity affiliates	1,459	2,866	3,448	5,695
Income tax effects on above	(420)	(427)	(935)	(816)
Net income attributable to ExlService Holdings, Inc. stockholders	1,039	2,439	2,513	4,879
Gain/ (loss) on foreign currency exchange contracts | Derivatives not designated as hedging instruments | Foreign currency exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Foreign exchange gain/(loss), net	$ (5,457)	$ (805)	$ (6,356)	$ (589)