FAIR VALUE OF FINANCIAL INSTRUMENTS - Financial Instruments Not Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Financial Assets [Abstract]
Securities held-to-maturity	$ 528,530	$ 516,930
Reported Value Measurement [Member]
Financial Assets [Abstract]
Cash and due from banks	626,056	457,547
Securities held-to-maturity	592,414	594,639
Loans held for investment, net	10,805,969	10,695,349
Accrued interest receivable	54,578	55,666
Financial Liabilities [Abstract]
Savings, money market and checking accounts	10,000,851	8,922,972
CDs	1,416,467	1,607,683
FHLBNY Advances	508,000	1,313,000
Subordinated debt, net	272,300	200,196
Accrued interest payable	14,845	17,298
Estimate of Fair Value Measurement [Member]
Financial Assets [Abstract]
Cash and due from banks	626,056	457,547
Securities held-to-maturity	528,530	516,930
Loans held for investment, net	10,435,847	10,305,026
Accrued interest receivable	54,578	55,666
Financial Liabilities [Abstract]
Savings, money market and checking accounts	10,000,851	8,922,972
CDs	1,414,003	1,602,087
FHLBNY Advances	508,764	1,312,940
Subordinated debt, net	257,278	160,696
Accrued interest payable	14,845	17,298
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]
Financial Assets [Abstract]
Cash and due from banks	626,056	457,547
Financial Liabilities [Abstract]
Savings, money market and checking accounts	10,000,851	8,922,972
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]
Financial Assets [Abstract]
Securities held-to-maturity	528,530	516,930
Accrued interest receivable	5,813	6,593
Financial Liabilities [Abstract]
CDs	1,414,003	1,602,087
FHLBNY Advances	508,764	1,312,940
Subordinated debt, net	257,278	160,696
Accrued interest payable	14,845	17,298
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]
Financial Assets [Abstract]
Loans held for investment, net	10,435,847	10,305,026
Accrued interest receivable	$ 48,765	$ 49,073