COST OF REVENUE (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Cost of Revenue [Abstract]
Compensation and benefits	$ 23,947	$ 30,463	$ 74,776	$ 108,637
Outside fees and services	34,013	61,314	123,914	182,483
Technology and telecommunications	8,776	8,586	27,082	27,124
Reimbursable expenses	2,810	7,213	14,495	16,484
Depreciation and amortization	3,024	2,753	9,512	10,160
Cost of real estate sold	0	393	0	42,763
Total	$ 72,570	$ 110,722	$ 249,779	$ 387,651