FAIR VALUE OF FINANCIAL INSTRUMENTS - Financial Instruments Not Measured at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Financial Assets [Abstract]
Securities held-to-maturity	$ 516,930	$ 505,759
Loans held for investment, net	6,300
Carrying Amount
Financial Assets [Abstract]
Cash and due from banks	457,547	169,297
Securities held-to-maturity	594,639	585,798
Loans held for investment, net	10,695,349	10,482,145
Accrued interest receivable	55,666	48,561
Financial Liabilities [Abstract]
Savings, money market and checking accounts	8,922,972	9,139,043
CDs	1,607,683	1,115,364
FHLBNY Advances	1,313,000	1,131,000
Subordinated debt, net	200,196	200,283
Other short-term borrowings		1,360
Accrued interest payable	17,298	5,323
Fair Value
Financial Assets [Abstract]
Cash and due from banks	457,547	169,297
Securities held-to-maturity	516,930	505,759
Loans held for investment, net	10,305,026	10,005,121
Accrued interest receivable	55,666	48,561
Financial Liabilities [Abstract]
Savings, money market and checking accounts	8,922,972	9,139,043
CDs	1,602,087	1,096,808
FHLBNY Advances	1,312,940	1,131,217
Subordinated debt, net	160,696	180,583
Other short-term borrowings		1,360
Accrued interest payable	17,298	5,323
Level 1 Inputs | Fair Value
Financial Assets [Abstract]
Cash and due from banks	457,547	169,297
Financial Liabilities [Abstract]
Savings, money market and checking accounts	8,922,972	9,139,043
Other short-term borrowings		1,360
Level 2 Inputs | Fair Value
Financial Assets [Abstract]
Securities held-to-maturity	516,930	505,759
Accrued interest receivable	6,593	6,105
Financial Liabilities [Abstract]
CDs	1,602,087	1,096,808
FHLBNY Advances	1,312,940	1,131,217
Subordinated debt, net	160,696	180,583
Accrued interest payable	17,298	5,323
Level 3 Inputs | Fair Value
Financial Assets [Abstract]
Loans held for investment, net	10,305,026	10,005,121
Accrued interest receivable	$ 49,073	$ 42,456