CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities:
Net income	$ 51,218	$ 43,235
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	14,650	11,377
Bad debt expense	946	988
Deferred taxes	275	735
Stock-based compensation expense	16,524	9,791
Excess tax benefit on stock-based compensation plans	(2,551)	(4,924)
Other	2,607	1,140
(Increase)/ decrease in operating assets:
Accounts receivable	(18,126)	(11,089)
Unbilled revenues	(26,070)	(31,373)
Prepaid expenses and other assets	525	1,422
Increase/ (decrease) in operating liabilities:
Accounts payable	(264)	2,475
Accrued expenses and other liabilities	6,346	(10,822)
Deferred revenues	(2,067)	(3,811)
Due to employees	7,121	2,581
Taxes payable	5,035	70
Net cash provided by operating activities	56,169	11,795
Cash flows from investing activities:
Purchases of property and equipment	(8,164)	(10,928)
Payment for construction of corporate facilities	(3,541)	(3,508)
Employee housing loans	(1,316)	(7,045)
Proceeds from repayments of employee housing loans	1,303	1,270
Decrease in restricted cash and time deposits, net	307	1,679
Increase in other long-term assets, net	(499)	(323)
Acquisition of businesses, net of cash acquired (Note 2)	(26,498)	(20)
Net cash used in investing activities	(38,408)	(18,875)
Cash flows from financing activities:
Proceeds related to stock options exercises	6,808	7,783
Excess tax benefit on stock-based compensation plans	2,551	4,924
Net cash provided by financing activities	9,359	12,707
Effect of exchange rate changes on cash and cash equivalents	(5,081)	(760)
Net increase in cash and cash equivalents	22,039	4,867
Cash and cash equivalents, beginning of period	169,207	118,112
Cash and cash equivalents, end of period	191,246	122,979
Noncash financing activities:
Deferred consideration payable	5,400	0
Contingent consideration payable	$ 28,225	$ 0