SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Equity Securities (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Debt and Equity Securities, FV-NI [Line Items]
Cost	$ 85,666		$ 99,859
Gross Unrealized Gain	19,240	$ 264,879
Gross Unrealized Loss	(23,522)	(2,960)
Fair Value	81,384		361,778
Equity securities - Life Sciences Portfolio (Note 3)
Debt and Equity Securities, FV-NI [Line Items]
Cost	38,066		56,037
Gross Unrealized Gain	19,232	262,811
Gross Unrealized Loss	(1,014)	(1,488)
Fair Value	56,284		317,360
Equity securities - other common stock
Debt and Equity Securities, FV-NI [Line Items]
Cost	47,600		43,822
Gross Unrealized Gain	8	2,068
Gross Unrealized Loss	(22,508)	$ (1,472)
Fair Value	$ 25,100		$ 44,418