COST OF REVENUE (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cost of Revenue [Abstract]
Compensation and benefits	$ 41,368	$ 54,866
Outside fees and services	62,581	65,098
Cost of real estate sold	2,094	3,179
Technology and telecommunications	8,509	9,451
Reimbursable expenses	4,496	8,147
Depreciation and amortization	5,056	6,453
Cost of revenue	$ 124,104	$ 147,194