CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net income	$ 23,641	$ 23,899
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	6,672	5,102
Bad debt (recovery)/expense	(517)	552
Deferred taxes	2,595	(482)
Stock-based compensation expense	15,776	10,964
Excess tax benefit on stock-based compensation plans	0	(2,040)
Other	651	50
(Increase)/decrease in operating assets:
Accounts receivable	24,635	16,993
Unbilled revenues	(39,485)	(18,559)
Prepaid expenses and other assets	(79)	(1,383)
Increase/(decrease) in operating liabilities:
Accounts payable	77	671
Accrued expenses and other liabilities	(18,484)	(34,153)
Due to employees	8,611	12,420
Taxes payable	7,135	(3,173)
Net cash provided by operating activities	31,228	10,861
Cash flows from investing activities:
Purchases of property and equipment	(5,725)	(6,185)
Employee housing loans issued	370	0
Proceeds from repayments of employee housing loans	689	470
Decrease in restricted cash and time deposits, net	38	30,000
Increase in other long-term assets, net	(313)	(774)
Other investing activities, net	37	(91)
Net cash (used in)/provided by investing activities	(5,644)	23,420
Cash flows from financing activities:
Proceeds from stock option exercises	10,606	3,108
Excess tax benefit on stock-based compensation plans	0	2,040
Payments of withholding taxes related to net share settlements of restricted stock units	(2,694)	0
Proceeds from debt (Note 4)	0	20,000
Repayment of debt (Note 4)	(30)	(15,031)
Proceeds from government grants	0	135
Acquisition of business, deferred consideration	0	(463)
Net cash provided by financing activities	7,882	9,789
Effect of exchange rate changes on cash and cash equivalents	2,928	1,358
Net increase in cash and cash equivalents	36,394	45,428
Cash and cash equivalents, beginning of period	362,025	199,449
Cash and cash equivalents, end of period	$ 398,419	$ 244,877