FAIR VALUE OF FINANCIAL INSTRUMENTS - Individually evaluated loans (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis [Abstract]
Individually evaluated loans outstanding balance, net of a valuation allowance	$ 10,778,048,000		$ 10,778,048,000		$ 10,483,324,000
Allowance for credit losses	72,563,000		72,563,000		83,507,000
Provision (recovery) for credit losses	1,806,000	$ 6,587,000	(950,000)	$ 5,039,000
Nonrecurring
Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis [Abstract]
Individually evaluated loans outstanding balance, net of a valuation allowance					2,500,000
Allowance for credit losses					1,300,000
Nonrecurring | Level 3 Inputs
Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis [Abstract]
Individually evaluated loans	352,000		352,000		1,179,000
Carrying Amount
Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis [Abstract]
Individually evaluated loans	10,777,696,000		10,777,696,000		10,482,145,000
Carrying Amount | Nonrecurring
Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis [Abstract]
Individually evaluated loans	352,000		352,000		$ 1,179,000
Collateral dependent loans | Nonrecurring
Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis [Abstract]
Provision (recovery) for credit losses	$ 0		$ 992,000