CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities:
Net income	$ 26,798	$ 25,420
Adjustments to reconcile net income to net cash (used in)/ provided by operating activities:
Depreciation and amortization	7,471	4,634
Bad debt provision/(recovery)	803	(7)
Deferred taxes	530	39
Excess tax benefit on stock-based compensation plans	(3,250)	(301)
Stock-based compensation	6,426	3,323
Non-cash stock charge	0	640
Other	1,139	(140)
Increase/ (decrease) in operating assets and liabilities:
Accounts receivable	(6,563)	(6,803)
Unbilled revenues	(24,695)	(12,241)
Prepaid expenses and other assets	981	955
Accounts payable	2,630	349
Accrued expenses	(12,695)	(14,516)
Deferred revenue	(3,059)	(2,482)
Due to employees	1,881	4,982
Taxes payable	(2,177)	(2,223)
Net cash (used in)/ provided by operating activities	(3,780)	1,629
Cash flows from investing activities:
Purchases of property and equipment	(8,998)	(6,410)
Payment for construction of corporate facilities	(1,006)	(3,232)
Employee housing loans	(5,172)	0
Proceeds from repayments of employee housing loans	821	0
Decrease in restricted cash, net	709	144
Increase in other long-term assets, net	(320)	(50)
Acquisitions of businesses, net of cash acquired	(20)	(6,990)
Net cash used in investing activities	(13,986)	(16,538)
Cash flows from financing activities:
Net proceeds from issuance of common stock in initial public offering	0	32,364
Costs related to stock issue	0	(1,766)
Repurchase of common stock	0	(50)
Excess tax benefit on stock-based compensation plans	3,250	301
Proceeds related to stock options exercises	5,353	248
Net cash provided by financing activities	8,603	31,097
Effect of exchange rate changes on cash and cash equivalents	(1,474)	(54)
Net (decrease)/ increase in cash and cash equivalents	(10,637)	16,134
Cash and cash equivalents, beginning of period	118,112	88,796
Cash and cash equivalents, end of period	$ 107,475	$ 104,930