CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (Unaudited)
Revenues	$ 160,384	$ 124,198
Operating expenses:
Cost of revenues (exclusive of depreciation and amortization)	102,454	77,937
Selling, general and administrative expenses	32,359	27,083
Depreciation and amortization expense	3,689	3,617
Other operating expenses, net	25	25
Income from operations	21,857	15,536
Interest and other income, net	976	630
Foreign exchange loss	(1,241)	(499)
Income before provision for income taxes	21,592	15,667
Provision for income taxes	4,228	2,987
Net income	17,364	12,680
Foreign currency translation adjustments	(3,577)	(2,343)
Comprehensive income	$ 13,787	$ 10,337
Net income per share:
Basic (in dollars per share)	$ 0.37	$ 0.28
Diluted (in dollars per share)	$ 0.35	$ 0.27
Shares used in calculation of net income per share:
Basic (in shares)	46,797	44,812
Diluted (in shares)	49,207	47,646