COST OF REVENUE (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Cost of Revenue [Abstract]
Compensation and benefits	$ 36,806	$ 54,769	$ 78,174	$ 109,635
Outside fees and services	58,588	68,879	121,169	133,977
Cost of real estate sold	40,276	13,320	42,370	16,499
Technology and telecommunications	8,317	10,852	16,826	20,303
Reimbursable expenses	4,775	9,008	9,271	17,155
Depreciation and amortization	3,879	6,378	8,935	12,831
Cost of revenue	$ 152,641	$ 163,206	$ 276,745	$ 310,400