INCOME TAXES - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Jun. 30, 2025	Mar. 31, 2025
Income Tax Contingency [Line Items]
Dividends	$ 35,300	$ 33,700
Dividends declared (in usd per share)	$ 0.64	$ 0.64
Cost of investments	$ 1,796,100	$ 1,776,100
Gross unrealized appreciation	103,800	117,400
Gross unrealized depreciation	119,700	108,200
Net unrealized appreciation (depreciation)	(15,900)	9,200
Total net deferred tax (liabilities) assets	(12,919)	$ (16,780)
RIC
Income Tax Contingency [Line Items]
Cost of investments	1,738,800
Gross unrealized appreciation	16,500
Gross unrealized depreciation	107,700
Net unrealized appreciation (depreciation)	(91,200)
Taxable Subsidiary
Income Tax Contingency [Line Items]
Cost of investments	57,300
Gross unrealized appreciation	87,300
Gross unrealized depreciation	12,000
Net unrealized appreciation (depreciation)	$ 75,300
O 2025 Q4 Dividends
Income Tax Contingency [Line Items]
Dividends declared (in usd per share)		$ 0.58
S 2025 Q4 Dividends
Income Tax Contingency [Line Items]
Dividends declared (in usd per share)		$ 0.06
O 2026 Q1 Dividends
Income Tax Contingency [Line Items]
Dividends declared (in usd per share)	$ 0.58
S 2026 Q1 Dividends
Income Tax Contingency [Line Items]
Dividends declared (in usd per share)	0.06
O 2025 M1 Dividends
Income Tax Contingency [Line Items]
Dividends declared (in usd per share)	0.1934
O 2025 M2 Dividends
Income Tax Contingency [Line Items]
Dividends declared (in usd per share)	0.1934
O 2025 M3 Dividends
Income Tax Contingency [Line Items]
Dividends declared (in usd per share)	0.1934
O 2025 Q3 Supplemental Dividends
Income Tax Contingency [Line Items]
Dividends declared (in usd per share)	$ 0.06