SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Equity Securities (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Debt and Equity Securities, FV-NI [Line Items]
Cost	$ 47,507		$ 63,383
Gross Unrealized Gain	24,653	$ 14,819
Gross Unrealized Loss	(7,649)	(16,594)
Fair Value	64,511		61,608
Equity securities - Life Sciences Portfolio
Debt and Equity Securities, FV-NI [Line Items]
Cost	28,498		28,498
Gross Unrealized Gain	21,978	14,815
Gross Unrealized Loss	(103)	(617)
Fair Value	50,373		42,696
Equity securities - other common stock
Debt and Equity Securities, FV-NI [Line Items]
Cost	19,009		34,885
Gross Unrealized Gain	2,675	4
Gross Unrealized Loss	(7,546)	$ (15,977)
Fair Value	$ 14,138		$ 18,912