CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (Unaudited)
Revenues	$ 140,150	$ 110,078	$ 397,532	$ 308,261
Operating expenses:
Cost of revenues (exclusive of depreciation and amortization)	88,539	69,099	250,023	193,077
Selling, general and administrative expenses	27,893	21,153	83,517	59,491
Depreciation and amortization expense	3,906	3,040	11,377	7,674
Other operating (income)/ expenses, net	(418)	50	(686)	669
Income from operations	20,230	16,736	53,301	47,350
Interest and other income, net	846	486	2,245	1,422
Foreign exchange loss	(720)	(635)	(2,088)	(1,949)
Income before provision for income taxes	20,356	16,587	53,458	46,823
Provision for income taxes	3,919	2,522	10,223	7,338
Net income	16,437	14,065	43,235	39,485
Foreign currency translation adjustments	2,975	2,704	(413)	1,852
Comprehensive income	19,412	16,769	42,822	41,337
Net income allocated to participating securities	0	0	0	(3,259)
Net income available for common stockholders	$ 16,437	$ 14,065	$ 43,235	$ 36,226
Net income per share:
Basic (in dollars per share)	$ 0.36	$ 0.33	$ 0.95	$ 0.93
Diluted (in dollars per share)	$ 0.34	$ 0.30	$ 0.90	$ 0.85
Shares used in calculation of net income per share:
Basic (in shares)	46,162	42,952	45,492	38,990
Diluted (in shares)	48,720	46,501	48,120	42,729