SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of fair value measurement of level 3 financial assets and liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Equity securities
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of period	$ 377,549	$ 149,292
Fair Value Adjustments	(4,543)	21,600
Relating to Undistributed Earnings	0	0
Purchases, Sales and Settlements	19,912	6,473
Transfer in and/or out of Level 3	(4,254)	(5,395)
Balance at End of period	388,664	171,970
Loans receivable at fair value
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of period	873,186	390,689
Fair Value Adjustments	10,937	10,726
Relating to Undistributed Earnings	3,238	2,082
Purchases, Sales and Settlements	(4,970)	(109,412)
Transfer in and/or out of Level 3	0	0
Balance at End of period	882,391	294,085
Mandatorily redeemable noncontrolling interests issued after November 5, 2003
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of period	4,506	4,700
Fair Value Adjustments	0	0
Relating to Undistributed Earnings	247	(186)
Purchases, Sales and Settlements	(251)	0
Transfer in and/or out of Level 3	0	0
Balance at End of period	4,502	$ 4,514
Contingent earnout
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at Beginning of period	0
Fair Value Adjustments	0
Relating to Undistributed Earnings	0
Purchases, Sales and Settlements	22,464
Transfer in and/or out of Level 3	0
Balance at End of period	$ 22,464