FAIR VALUE OF FINANCIAL INSTRUMENTS - Balance Sheet Groupings (Details) - USD ($)	Jun. 30, 2022	Dec. 31, 2021	Jan. 01, 2021
Financial Assets [Abstract]
Securities held-to-maturity	$ 531,870,000	$ 177,354,000	$ 0
Carrying Amount
Financial Assets [Abstract]
Cash and due from banks	281,487,000	393,722,000
Securities held-to-maturity	579,965,000	179,309,000
Loans held for investment, net	9,580,302,000	9,158,908,000
Accrued interest receivable	38,382,000	40,149,000
Financial Liabilities [Abstract]
Savings, money market and checking accounts	9,606,689,000	9,605,731,000
Certificates of Deposits ("CDs")	959,312,000	853,242,000
FHLBNY Advances	100,000,000	25,000,000
Subordinated debt, net	200,327,000	197,096,000
Other short-term borrowings	2,162,000	1,862,000
Accrued interest payable	2,184,000	870,000
Fair Value
Financial Assets [Abstract]
Cash and due from banks	281,487,000	393,722,000
Securities held-to-maturity	531,870,000	177,354,000
Loans held for investment, net	9,423,799,000	9,169,872,000
Accrued interest receivable	38,382,000	40,149,000
Financial Liabilities [Abstract]
Savings, money market and checking accounts	9,606,689,000	9,605,731,000
Certificates of Deposits ("CDs")	952,339,000	857,342,000
FHLBNY Advances	99,933,000	25,014,000
Subordinated debt, net	194,127,000	202,334,000
Other short-term borrowings	2,162,000	1,862,000
Accrued interest payable	2,184,000	870,000
Level 1 Inputs | Fair Value
Financial Assets [Abstract]
Cash and due from banks	281,487,000	393,722,000
Financial Liabilities [Abstract]
Savings, money market and checking accounts	9,606,689,000	9,605,731,000
Other short-term borrowings	2,162,000	1,862,000
Level 2 Inputs | Fair Value
Financial Assets [Abstract]
Securities held-to-maturity	531,870,000	177,354,000
Accrued interest receivable	4,557,000	4,481,000
Financial Liabilities [Abstract]
Certificates of Deposits ("CDs")	952,339,000	857,342,000
FHLBNY Advances	99,933,000	25,014,000
Subordinated debt, net	194,127,000	202,334,000
Accrued interest payable	2,184,000	870,000
Level 3 Inputs | Fair Value
Financial Assets [Abstract]
Loans held for investment, net	9,423,799,000	9,169,872,000
Accrued interest receivable	$ 33,825,000	$ 35,668,000