DIVIDENDS, DISTRIBUTIONS AND TAXABLE INCOME - Reconciliation to Taxable Income and to Total Distributions Declared to Common Stockholders (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Net increase in net assets resulting from operations	$ 55,338	$ 14,749	$ 65,203	$ 83,956	$ 95,110	$ 57,346	$ 135,287	$ 236,413
Book-tax difference from share-based compensation expense							(3,456)	(5,436)
Net unrealized (appreciation) depreciation	10,081			(38,631)			19,922	(117,072)
Income tax provision	$ 2,060			$ 12,284			17,477	22,691
Pre-tax book income not consolidated for tax purposes							(28,333)	(35,701)
Book income and tax income differences, including debt origination, structuring fees, dividends, realized gains and changes in estimates							24,026	6,027
Estimated taxable income							164,923	106,922
Taxable income earned in prior year and carried forward for distribution in current year							50,834	24,350
Taxable income earned prior to period end and carried forward for distribution next period							(71,128)	(18,959)
Dividend payable as of period end and paid in the following period							16,789	14,553
Total distributions accrued or paid to common stockholders							$ 161,418	$ 126,866