CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net income	$ 61,994	$ 54,484	$ 44,353
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	15,120	10,882	7,538
Bad debt expense	335	662	727
Deferred taxes	41	(3,933)	497
Stock-based compensation expense	13,150	6,826	2,866
Excess tax benefits on stock-based compensation plans	(6,201)	(3,297)	0
Non-cash stock charge	0	640	0
Goodwill impairment loss	0	0	1,697
Other	1,199	(66)	777
(Increase)/ decrease in operating assets:
Accounts receivable	(17,302)	(12,664)	(19,030)
Unbilled revenues	(9,833)	(6,905)	(1,004)
Prepaid expenses and other assets	587	(1,339)	(1,694)
Increase/ (decrease) in operating liabilities:
Accounts payable	(2,900)	1,407	254
Accrued expenses and other liabilities	501	(5,825)	9,474
Deferred revenues	(2,325)	(767)	1,843
Due to employees	785	2,896	2,796
Taxes payable	3,074	5,498	3,426
Net cash provided by operating activities	58,225	48,499	54,520
Cash flows from investing activities:
Purchases of property and equipment	(13,360)	(13,376)	(15,548)
Payments for construction of corporate facilities	(2,560)	(13,701)	(1,545)
Issuance of employee housing loans	(7,982)	0	0
Proceeds from repayments of employee housing loans	2,189	0	0
Decrease/(increase) in restricted cash, net (Note 6)	429	470	(144)
Increase in other long-term assets, net	(516)	(69)	(171)
Acquisition of businesses, net of cash acquired (Note 2)	(20)	(32,951)	0
Net cash used in investing activities	(21,820)	(59,627)	(17,408)
Cash flows from financing activities:
Proceeds related to stock options exercises	9,300	4,951	72
Excess tax benefits on stock-based compensation plans	6,201	3,297	0
Net proceeds from issuance of common stock in initial public offering	0	32,364	0
Costs related to stock issue	0	(1,765)	(1,630)
Proceeds related to line of credit	0	0	5,000
Repayment related to line of credit	0	0	(5,000)
* Net cash provided by/(used in) financing activities *	15,501	38,847	(1,558)
Effect of exchange-rate changes on cash and cash equivalents	(811)	1,597	(762)
Net increase in cash and cash equivalents	51,095	29,316	34,792
Cash and cash equivalents, beginning of year-January 1	118,112	88,796	54,004
Cash and cash equivalents, end of year	169,207	118,112	88,796
Cash paid during the year for:
Income taxes	10,207	13,065	7,007
Bank interest	$ 26	$ 14	$ 37