COMMITMENTS AND CONTINGENCIES (Details)	3 Months Ended
	Mar. 31, 2020 USD ($) loan institution transaction	Mar. 31, 2019 USD ($) transaction	Jan. 01, 2020 USD ($)	Dec. 31, 2019 USD ($) loan
Guarantor Obligations [Line Items]
Provision for losses at the time of sale	$ 56,646,000	$ 7,654,000
Number of unrelated financial institutions | institution	4
Derivative transaction held for guarantee | loan	202			172
Notional	$ 734,909,000			$ 502,172,000
Aggregate fair value of swaps to customers, liability	(84,300,000)			(26,400,000)
Allowance for credit losses	139,073,000	46,321,000		47,576,000
Provision for credit losses	56,646,000	$ 7,654,000
Provision	3,451,000
Impact of ASC 326 Adoption
Guarantor Obligations [Line Items]
Allowance for credit losses				35,855,000
Unfunded Lending Commitment
Guarantor Obligations [Line Items]
Provision for losses at the time of sale	(200,000)
Allowance for credit losses	4,300,000			1,500,000
Provision for credit losses	(200,000)
Provision	$ 200,000
Unfunded Lending Commitment | Impact of ASC 326 Adoption
Guarantor Obligations [Line Items]
Allowance for credit losses			$ 3,000,000.0
Minimum
Guarantor Obligations [Line Items]
Notional amount maturity period	1 year
Maximum
Guarantor Obligations [Line Items]
Notional amount maturity period	15 years
Interest Rate Swap
Guarantor Obligations [Line Items]
Derivative transaction held for guarantee | loan	200
Notional	$ 1,000,000,000.0			$ 941,000,000.0
Aggregate fair value of swaps to customers, liability	(85,500,000)
Secondary Market Loan Sales
Guarantor Obligations [Line Items]
Provision for losses at the time of sale	$ 0
Number of loans repurchased | transaction	0	1
Loans repurchased		$ 200,000
Provision for credit losses	$ 0