FAIR VALUE OF FINANCIAL INSTRUMENTS - Financial Instruments Not Measured at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Financial Assets [Abstract]
Securities held-to-maturity	$ 520,069	$ 505,759
Carrying Amount
Financial Assets [Abstract]
Cash and due from banks	452,504	169,297
Securities held-to-maturity	603,960	585,798
Loans held for investment, net	10,800,417	10,482,145
Accrued interest receivable	51,787	48,561
Financial Liabilities [Abstract]
Savings, money market and checking accounts	8,991,943	9,139,043
Certificates of Deposits ("CDs")	1,530,749	1,115,364
FHLBNY Advances	1,448,000	1,131,000
Subordinated debt, net	200,240	200,283
Other short-term borrowings		1,360
Accrued interest payable	18,098	5,323
Fair Value
Financial Assets [Abstract]
Cash and due from banks	452,504	169,297
Securities held-to-maturity	520,069	505,759
Loans held for investment, net	10,245,728	10,005,121
Accrued interest receivable	51,787	48,561
Financial Liabilities [Abstract]
Savings, money market and checking accounts	8,991,943	9,139,043
Certificates of Deposits ("CDs")	1,522,515	1,096,808
FHLBNY Advances	1,444,184	1,131,217
Subordinated debt, net	158,240	180,583
Other short-term borrowings		1,360
Accrued interest payable	18,098	5,323
Level 1 Inputs | Fair Value
Financial Assets [Abstract]
Cash and due from banks	452,504	169,297
Financial Liabilities [Abstract]
Savings, money market and checking accounts	8,991,943	9,139,043
Other short-term borrowings		1,360
Level 2 Inputs | Fair Value
Financial Assets [Abstract]
Securities held-to-maturity	520,069	505,759
Accrued interest receivable	6,205	6,105
Financial Liabilities [Abstract]
Certificates of Deposits ("CDs")	1,522,515	1,096,808
FHLBNY Advances	1,444,184	1,131,217
Subordinated debt, net	158,240	180,583
Accrued interest payable	18,098	5,323
Level 3 Inputs | Fair Value
Financial Assets [Abstract]
Loans held for investment, net	10,245,728	10,005,121
Accrued interest receivable	$ 45,582	$ 42,456