SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings (accumulated deficit)	$ (137,859)		$ 51,534
Incentive income compensation vesting period	5 years
Adoption of new accounting guidance (ASU 2016-13)		$ (356)
Retained Earnings (Accumulated Deficit)
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Adoption of new accounting guidance (ASU 2016-13)		(220)
Retained Earnings (Accumulated Deficit) | Accounting Standards Update 2016-13
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Adoption of new accounting guidance (ASU 2016-13)		$ (400)
Minimum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Withdrawal period	1 month
Minimum | Furniture, equipment and capitalized software
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Estimated useful life (in years)	3 years
Minimum | Acquired intangibles
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Useful lives (in years)	7 years
Minimum | Contractual Rights to Earn Future Fee Income
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Useful lives (in years)	7 years
Maximum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Withdrawal period	3 years
Maximum | Furniture, equipment and capitalized software
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Estimated useful life (in years)	5 years
Maximum | Acquired intangibles
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Useful lives (in years)	25 years
Maximum | Contractual Rights to Earn Future Fee Income
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Useful lives (in years)	25 years
Management fees | Minimum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Management fees payment term (years)	10 years
Management fees | Maximum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Management fees payment term (years)	11 years
Closed-end and Evergreen
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Percentage of fund profits	20.00%
Preferred return on funds	8.00%
Evergreen
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Percentage of fund profits	20.00%