SIGNIFICANT SUBSIDIARIES - Summarized Financial Information Operation Statement (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Investment Company, Nonconsolidated Subsidiary [Line Items]
Net investment income	$ 14,444	$ 12,438	$ 9,726	$ 9,043	$ 26,882	$ 18,769
Total investment income	14,978		10,040		27,608	19,479
Net unrealized depreciation (appreciation) on investments	3,649	$ (12,248)	(691)	$ 7,051	(8,599)	6,360
I-45 SLF LLC
Investment Company, Nonconsolidated Subsidiary [Line Items]
Total revenues	4,292		3,026		7,569	6,148
Total expenses	(1,739)		(921)		(3,058)	(2,018)
Net investment income	2,553		2,105		4,511	4,130
Net unrealized depreciation (appreciation) on investments	(1,060)		(1,261)		(8,491)	(1,198)
Realized and Unrealized Gain (Loss), Investment, Derivative, and Foreign Currency Transaction, Operating, after Tax	13		(896)		71	173
Net increase (decrease) in members’ equity resulting from operations	$ 1,506		$ (52)		$ (3,909)	$ 3,105