COST OF REVENUE (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
COST OF REVENUE
Compensation and benefits	$ 28,840	$ 22,497	$ 84,314	$ 59,296
Outside fees and services	31,084	21,528	91,494	57,221
Reimbursable expenses	24,326	21,834	77,846	56,934
Technology and communications	6,900	5,904	17,890	13,439
Depreciation and amortization	3,137	1,576	7,241	4,495
Total	$ 94,287	$ 73,339	$ 278,785	$ 191,385