Segment & Geographical Information - Revenues and Cost of Revenues for Company's Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues and cost of revenues for Company's reportable segments [Line Items]
Revenues, net	$ 177,274	$ 171,200	$ 170,478	$ 167,036	$ 165,858	$ 163,503	$ 155,621	$ 143,510	$ 685,988	$ 628,492	$ 499,278
Cost of revenues (exclusive of depreciation and amortization)									447,956	402,917	332,535
Gross profit	61,490	59,433	58,452	58,657	59,742	60,305	55,143	50,385	238,032	225,575	166,743
Operating expenses									173,810	158,232	132,703
Foreign exchange gain, interest expense and other income, net									19,662	8,433	3,598
Income tax expense									22,151	24,211	5,193
Net income	$ 15,488	$ 16,050	$ 16,375	$ 13,820	$ 14,762	$ 15,162	$ 12,074	$ 9,567	61,733	51,565	32,445
Insurance [Member]
Revenues and cost of revenues for Company's reportable segments [Line Items]
Revenues, net									206,327	199,878	151,308
Cost of revenues (exclusive of depreciation and amortization)									146,203	134,196	107,026
Gross profit									60,124	65,682	44,282
Healthcare [Member]
Revenues and cost of revenues for Company's reportable segments [Line Items]
Revenues, net									68,656	55,209	42,848
Cost of revenues (exclusive of depreciation and amortization)									44,098	37,224	29,598
Gross profit									24,558	17,985	13,250
Travel, Transportation and Logistics [Member]
Revenues and cost of revenues for Company's reportable segments [Line Items]
Revenues, net									69,366	62,264	47,492
Cost of revenues (exclusive of depreciation and amortization)									41,962	37,506	29,945
Gross profit									27,404	24,758	17,547
Finance and Accounting [Member]
Revenues and cost of revenues for Company's reportable segments [Line Items]
Revenues, net									79,416	78,504	92,013
Cost of revenues (exclusive of depreciation and amortization)									48,302	46,846	56,770
Gross profit									31,114	31,658	35,243
Other Operations Management [Member]
Revenues and cost of revenues for Company's reportable segments [Line Items]
Revenues, net									96,489	110,486	100,002
Cost of revenues (exclusive of depreciation and amortization)									61,050	68,307	63,154
Gross profit									35,439	42,179	36,848
Analytics
Revenues and cost of revenues for Company's reportable segments [Line Items]
Revenues, net									165,734	122,151	65,615
Cost of revenues (exclusive of depreciation and amortization)									106,341	78,838	46,042
Gross profit									59,393	43,313	19,573
BPM Services [Member]
Revenues and cost of revenues for Company's reportable segments [Line Items]
Revenues, net									520,254	506,341	433,663
Analytics Services [Member]
Revenues and cost of revenues for Company's reportable segments [Line Items]
Revenues, net									$ 165,734	$ 122,151	$ 65,615