CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net income	$ 33,945	$ 32,178
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	8,103	9,140
Bad debt expense	701	769
Deferred taxes	372	195
Stock-based compensation expense	21,387	9,099
Excess tax benefit on stock-based compensation plans	(2,382)	(2,161)
Other	2,085	2,336
(Increase)/ decrease in operating assets:
Accounts receivable	(13,209)	(7,172)
Unbilled revenues	(35,935)	(24,254)
Prepaid expenses and other assets	(7,935)	1,000
Increase/ (decrease) in operating liabilities:
Accounts payable	7,743	5,899
Accrued expenses and other liabilities	(4,160)	(2,172)
Deferred revenues	(459)	(255)
Due to employees	3,602	6,627
Taxes payable	(4,824)	1,798
Net cash provided by operating activities	9,034	33,027
Cash flows from investing activities:
Purchases of property and equipment	(5,342)	(4,445)
Payment for construction of corporate facilities	(3,512)	(2,282)
Employee housing loans issued	(919)	(799)
Proceeds from repayments of employee housing loans	1,090	856
Increase in restricted cash and time deposits, net	(29,955)	303
Increase in other long-term assets, net	(811)	(346)
Acquisition of businesses, net of cash acquired (Note 2)	(30)	(26,498)
Net cash used in investing activities	(39,479)	(33,211)
Cash flows from financing activities:
Proceeds related to stock options exercises	13,955	5,413
Excess tax benefit on stock-based compensation plans	2,382	2,161
Acquisition of business, deferred consideration (Note 2)	(30,274)	0
Net cash provided by/ (used in) financing activities	(13,937)	7,574
Effect of exchange rate changes on cash and cash equivalents	(435)	(1,522)
Net increase/ (decrease) in cash and cash equivalents	(44,817)	5,868
Cash and cash equivalents, beginning of period	220,534	169,207
Cash and cash equivalents, end of period	$ 175,717	$ 175,075