FAIR VALUE OF FINANCIAL INSTRUMENTS - Financial Instruments Not Measured at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Financial Assets [Abstract]
Securities held-to-maturity	$ 502,837	$ 516,930
Reported Value Measurement [Member]
Financial Assets [Abstract]
Cash and due from banks	413,983	457,547
Securities held-to-maturity	588,000	594,639
Loans held for investment, net	10,746,223	10,695,349
Accrued interest receivable	55,588	55,666
Financial Liabilities [Abstract]
Savings, money market and checking accounts	9,646,163	8,922,972
CDs	1,382,271	1,607,683
FHLBNY Advances	633,000	1,313,000
Subordinated debt, net	262,814	200,196
Accrued interest payable	14,101	17,298
Estimate of Fair Value Measurement [Member]
Financial Assets [Abstract]
Cash and due from banks	413,983	457,547
Securities held-to-maturity	502,837	516,930
Loans held for investment, net	10,233,958	10,305,026
Accrued interest receivable	55,588	55,666
Financial Liabilities [Abstract]
Savings, money market and checking accounts	9,646,163	8,922,972
CDs	1,377,848	1,602,087
FHLBNY Advances	633,362	1,312,940
Subordinated debt, net	227,214	160,696
Accrued interest payable	14,101	17,298
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]
Financial Assets [Abstract]
Cash and due from banks	413,983	457,547
Financial Liabilities [Abstract]
Savings, money market and checking accounts	9,646,163	8,922,972
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]
Financial Assets [Abstract]
Securities held-to-maturity	502,837	516,930
Accrued interest receivable	6,415	6,593
Financial Liabilities [Abstract]
CDs	1,377,848	1,602,087
FHLBNY Advances	633,362	1,312,940
Subordinated debt, net	227,214	160,696
Accrued interest payable	14,101	17,298
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]
Financial Assets [Abstract]
Loans held for investment, net	10,233,958	10,305,026
Accrued interest receivable	$ 49,173	$ 49,073