Segment and Geographical Information - Revenues and Cost of Revenues for Company's Reportable Segments (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues and cost of revenues for Company's reportable segments [Line Items]
Revenues, net		$ 1,630,668	$ 1,412,044	$ 1,122,293
Cost of revenues	[1]	1,022,902	896,595	690,934
Gross profit	[1]	607,766	515,449	431,359
Operating expenses		369,011	323,287	275,478
Foreign exchange gain, net, interest expense and other income, net		(814)	(2,063)	(9,320)
Income tax expense		53,536	47,565	31,850
Gain from equity-method investment		153	434	47
Net income attributable to ExlService Holdings, Inc. stockholders		184,558	142,968	114,758
Digital operations and solutions
Revenues and cost of revenues for Company's reportable segments [Line Items]
Revenues, net		901,541	764,693	661,621
Analytics services
Revenues and cost of revenues for Company's reportable segments [Line Items]
Revenues, net		729,127	647,351	460,672
Insurance
Revenues and cost of revenues for Company's reportable segments [Line Items]
Revenues, net		529,855	448,704	381,999
Cost of revenues		341,785	287,734	239,529
Gross profit		188,070	160,970	142,470
Healthcare
Revenues and cost of revenues for Company's reportable segments [Line Items]
Revenues, net		105,994	97,351	112,386
Cost of revenues		69,273	70,951	69,760
Gross profit		36,721	26,400	42,626
Emerging Business
Revenues and cost of revenues for Company's reportable segments [Line Items]
Revenues, net		265,692	218,638	167,236
Cost of revenues		150,943	128,017	91,737
Gross profit		114,749	90,621	75,499
Analytics
Revenues and cost of revenues for Company's reportable segments [Line Items]
Revenues, net		729,127	647,351	460,672
Cost of revenues		460,901	409,893	289,908
Gross profit		$ 268,226	$ 237,458	$ 170,764

[1] Exclusive of depreciation and amortization expense.