COMMITMENTS AND CONTINGENCIES (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2018	Dec. 31, 2017
COMMITMENTS AND CONTINGENCIES
Unfunded capital commitments		$ 284,500,000	$ 285,700,000
Performance Income
Performance Income
Performance income subject to potential clawback provision		472,900,000	476,100,000
Performance income subject to potential claw back provision that are reimbursable by professionals		367,500,000	370,000,000
Performance income subject to potential claw back provision, repayment obligation		200,000
Kayne Anderson Capital Advisors L.P.
COMMITMENTS AND CONTINGENCIES
Unfunded capital commitments		$ 16,300,000	$ 16,500,000
American Capital Ltd | ARCC
COMMITMENTS AND CONTINGENCIES
Maximum fees waived	$ 10,000,000
Term of fee waiver	30 months
Maximum amount shortfall that will not carryover, less than	$ 10,000,000
Remaining term		15 months
Remaining fees waived		$ 50,000,000