FAIR VALUE OF FINANCIAL INSTRUMENTS - Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Financial Assets
Derivative assets	$ 177,369	$ 154,485
Financial Liabilities
Derivative liabilities	160,712	137,335
Recurring | Cash flow hedges
Financial Assets
Derivative assets	16,657	17,150
Recurring | Freestanding derivatives, net
Financial Assets
Derivative assets	160,712	137,335
Financial Liabilities
Derivative liabilities	160,712	137,335
Recurring | Level 2 Inputs | Cash flow hedges
Financial Assets
Derivative assets	16,657	17,150
Recurring | Level 2 Inputs | Freestanding derivatives, net
Financial Assets
Derivative assets	160,712	137,335
Financial Liabilities
Derivative liabilities	160,712	137,335
Nonrecurring | Level 3 Inputs
Certain individually evaluated loans
Individually evaluated loans	352	1,179
Carrying Amount
Certain individually evaluated loans
Individually evaluated loans	10,777,696	10,482,145
Carrying Amount | Nonrecurring
Certain individually evaluated loans
Individually evaluated loans	352	1,179
US Government Agencies Debt Securities [Member] | Recurring
Financial Assets
Securities available-for-sale:	9,143
US Government Agencies Debt Securities [Member] | Recurring | Level 2 Inputs
Financial Assets
Securities available-for-sale:	9,143
US Treasury Securities [Member] | Recurring
Financial Assets
Securities available-for-sale:	229,873	227,256
US Treasury Securities [Member] | Recurring | Level 2 Inputs
Financial Assets
Securities available-for-sale:	229,873	227,256
Corporate securities | Recurring
Financial Assets
Securities available-for-sale:	141,087	166,773
Corporate securities | Recurring | Level 2 Inputs
Financial Assets
Securities available-for-sale:	141,087	166,773
Pass-through mortgage-backed securities ("MBS") issued by government sponsored entities ("GSEs") | Recurring
Financial Assets
Mortgage-backed securities	206,203	241,240
Pass-through mortgage-backed securities ("MBS") issued by government sponsored entities ("GSEs") | Recurring | Level 2 Inputs
Financial Assets
Mortgage-backed securities	206,203	241,240
Agency collateralized mortgage obligations ("CMOs") | Recurring
Financial Assets
Securities available-for-sale:	255,642	281,339
Agency collateralized mortgage obligations ("CMOs") | Recurring | Level 2 Inputs
Financial Assets
Securities available-for-sale:	255,642	281,339
State and municipal obligations. | Recurring
Financial Assets
Securities available-for-sale:	27,931	33,979
State and municipal obligations. | Recurring | Level 2 Inputs
Financial Assets
Securities available-for-sale:	$ 27,931	$ 33,979