Segment Information - Revenues and Cost of Revenues for Company's Outsourcing Services and Transformation Services Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenues and cost of revenues for Company's outsourcing services and transformation services segments [Line Items]
Revenues	$ 119,738	$ 116,008	$ 241,535	$ 232,014
Cost of revenues (exclusive of depreciation and amortization)	81,259	73,930	156,181	146,843
Gross profit	38,479	42,078	85,354	85,171
Operating expenses	32,382	29,251	63,770	60,239
Other income/(expense)	721	24	847	678
Income tax provision	(944)	3,615	3,521	6,612
Net income	7,762	9,236	18,910	18,998
Outsourcing Services [Member]
Revenues and cost of revenues for Company's outsourcing services and transformation services segments [Line Items]
Revenues	94,314	97,328	194,405	194,900
Cost of revenues (exclusive of depreciation and amortization)	62,494	59,483	121,393	118,959
Gross profit	31,820	37,845	73,012	75,941
Transformation Services [Member]
Revenues and cost of revenues for Company's outsourcing services and transformation services segments [Line Items]
Revenues	25,424	18,680	47,130	37,114
Cost of revenues (exclusive of depreciation and amortization)	18,765	14,447	34,788	27,884
Gross profit	$ 6,659	$ 4,233	$ 12,342	$ 9,230