FAIR VALUE OF FINANCIAL INSTRUMENTS - Financial Instruments Not Measured at Fair Value (Details) - USD ($)	Sep. 30, 2022	Dec. 31, 2021	Jan. 01, 2021
Financial Assets [Abstract]
Securities held-to-maturity	$ 511,054,000	$ 177,354,000	$ 0
Carrying Amount
Financial Assets [Abstract]
Cash and due from banks	312,996,000	393,722,000
Securities held-to-maturity	591,403,000	179,309,000
Loans held for investment, net	10,033,553,000	9,158,908,000
Accrued interest receivable	41,567,000	40,149,000
Financial Liabilities [Abstract]
Savings, money market and checking accounts	9,557,896,000	9,605,731,000
Certificates of Deposits ("CDs")	930,774,000	853,242,000
FHLBNY Advances	620,000,000	25,000,000
Subordinated debt, net	200,305,000	197,096,000
Other short-term borrowings	2,124,000	1,862,000
Accrued interest payable	4,548,000	870,000
Fair Value
Financial Assets [Abstract]
Cash and due from banks	312,996,000	393,722,000
Securities held-to-maturity	511,054,000	177,354,000
Loans held for investment, net	9,594,094,000	9,169,872,000
Accrued interest receivable	41,567,000	40,149,000
Financial Liabilities [Abstract]
Savings, money market and checking accounts	9,557,896,000	9,605,731,000
Certificates of Deposits ("CDs")	922,132,000	857,342,000
FHLBNY Advances	619,993,000	25,014,000
Subordinated debt, net	184,305,000	202,334,000
Other short-term borrowings	2,124,000	1,862,000
Accrued interest payable	4,548,000	870,000
Level 1 Inputs | Fair Value
Financial Assets [Abstract]
Cash and due from banks	312,996,000	393,722,000
Financial Liabilities [Abstract]
Savings, money market and checking accounts	9,557,896,000	9,605,731,000
Other short-term borrowings	2,124,000	1,862,000
Level 2 Inputs | Fair Value
Financial Assets [Abstract]
Securities held-to-maturity	511,054,000	177,354,000
Accrued interest receivable	4,971,000	4,481,000
Financial Liabilities [Abstract]
Certificates of Deposits ("CDs")	922,132,000	857,342,000
FHLBNY Advances	619,993,000	25,014,000
Subordinated debt, net	184,305,000	202,334,000
Accrued interest payable	4,548,000	870,000
Level 3 Inputs | Fair Value
Financial Assets [Abstract]
Loans held for investment, net	9,594,094,000	9,169,872,000
Accrued interest receivable	$ 36,596,000	$ 35,668,000