EQUITY SECURITIES PORTFOLIO INVESTMENT - Narrative (Details) $ in Thousands, £ in Millions			12 Months Ended
	Apr. 03, 2020 USD ($)	Apr. 03, 2020 GBP (£)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 03, 2020
Offsetting Liabilities [Line Items]
Fair value of investment			$ 63,068	$ 61,608
Earnings on equity investment in joint venture			4,167	42,531
Net income including noncontrolling interests in subsidiaries			67,060	(125,065)
Net income attributable to noncontrolling interests in subsidiaries			1,870	14,126
Interest income, other			146	291
Life Sciences Portfolio
Offsetting Liabilities [Line Items]
Investment at fair value			82,800	68,400
Acacia
Offsetting Liabilities [Line Items]
Distributions received			2,800	28,400
Noncontrolling Interests
Offsetting Liabilities [Line Items]
Distributions received			1,400	14,100
Arix
Offsetting Liabilities [Line Items]
Fair value of investment			$ 57,100
Arix | Arix
Offsetting Liabilities [Line Items]
Equity method investment ownership			26.00%
MalinJ1
Offsetting Liabilities [Line Items]
Ownership percentage					63.90%
Earnings on equity investment in joint venture			$ 4,200	$ 42,500
MalinJ1 | MalinJ1
Offsetting Liabilities [Line Items]
Equity method investment ownership			41.00%
Option Agreement | Portfolio Companies
Offsetting Liabilities [Line Items]
Payments to acquire investments	$ 277,500	£ 223.9