COMMITMENTS AND CONTINGENCIES - Allowance for Unfunded Commitments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance, Allowance	$ 199,422	$ 38,189
Provision for unfunded commitments	(16,579)	37,047
Ending balance, Allowance	178,570	149,524
Unfunded Loan Commitments
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance, Allowance	32,854	1,077
Provision for unfunded commitments	(11,839)	4,000
Ending balance, Allowance	21,015	17,791
Unfunded Loan Commitments | Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance, Allowance	$ 0	$ 12,714