FAIR VALUE OF FINANCIAL INSTRUMENTS - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		15 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	$ 742,378		$ 742,378	$ 462,665
Loans held for sale forgiven	155,300		201,700
Revenue	5,057,270	$ 1,381,109
Paycheck Protection Program, CARES Act Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	692,400		$ 692,400
Revenue	9,400
Loans Receivable Held-For-Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Excess amortized cost over fair value of loans	$ 900	$ 22,000