SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)	12 Months Ended
	Dec. 31, 2019 USD ($) entity	Dec. 31, 2018 USD ($) entity	Dec. 31, 2017 USD ($)
Consolidated CLOs
Number of CLOs consolidated | entity	16	13
Management Fees
Carried interest, contingent repayment obligations	$ 0	$ 400,000
Incentive Fees
Adoption of ASU			$ 0
Foreign Currency
Foreign currency transaction gain (loss)	$ 8,500,000	$ 100,000	$ 1,700,000
ARCC
Management Fees
Management fees as a percentage of net investment income	20.00%
Hurdle rate per quarter	1.75%
Hurdle rate per annum	7.00%
Percentage of net investment income received from first dollar earned	20.00%
Minimum
Goodwill and Intangible Assets
Estimated useful lives, intangible assets	2 years 2 months 12 days
Incentive Fees
Performance fee compensation, employment or service period	4 years
Minimum | Property Plant And Equipment Other Than Leasehold Improvements And Internal Use Software
Fixed Assets
Estimated useful life	3 years
Maximum
Goodwill and Intangible Assets
Estimated useful lives, intangible assets	8 years 6 months
Incentive Fees
Performance fee compensation, employment or service period	6 years
Maximum | Property Plant And Equipment Other Than Leasehold Improvements And Internal Use Software
Fixed Assets
Estimated useful life	7 years