COST OF REVENUE (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
COST OF REVENUE
Compensation and benefits	$ 27,989	$ 19,959	$ 55,474	$ 36,799
Outside fees and services	31,757	17,532	60,410	35,693
Reimbursable expenses	24,814	19,459	53,520	35,100
Technology and communications	5,866	4,557	10,990	7,535
Depreciation and amortization	2,312	1,590	4,104	2,919
Total	$ 92,738	$ 63,097	$ 184,498	$ 118,046