FAIR VALUE OF FINANCIAL INSTRUMENTS - Schedule of Basis and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financial assets:
Held-to-maturity securities	$ 1,521,621	$ 1,549,509
Carrying Value
Financial assets:
Cash and cash equivalents	155,204	90,570
Held-to-maturity securities	1,673,962	1,696,834
Loans held for sale	2,137	1,817
Loans receivable, net	4,359,380	4,345,628
Resell agreements	131,242	50,000
Accrued interest receivable	53,436	55,484
Financial liabilities:
FHLBNY advances	9,135	4,381
Subordinated debt, net	70,570	70,546
Accrued interest payable	6,640	12,270
Carrying Value | Deposits payable on demand
Financial liabilities:
Deposits	6,946,272	6,582,321
Carrying Value | Time deposits and brokered CDs
Financial liabilities:
Deposits	359,493	429,667
Carrying Value | Other borrowings
Financial liabilities:
Other borrowings	60,000	230,000
Estimated Fair Value
Financial assets:
Cash and cash equivalents	155,204	90,570
Held-to-maturity securities	1,521,621	1,549,509
Loans held for sale	2,137	1,817
Loans receivable, net	4,026,693	4,029,142
Resell agreements	131,242	50,000
Accrued interest receivable	53,436	55,484
Financial liabilities:
FHLBNY advances	8,818	4,381
Subordinated debt, net	56,456	56,790
Accrued interest payable	6,640	12,270
Estimated Fair Value | Deposits payable on demand
Financial liabilities:
Deposits	6,946,272	6,582,321
Estimated Fair Value | Time deposits and brokered CDs
Financial liabilities:
Deposits	357,684	428,116
Estimated Fair Value | Other borrowings
Financial liabilities:
Other borrowings	59,958	229,711
Estimated Fair Value | Level 1
Financial assets:
Cash and cash equivalents	155,204	90,570
Held-to-maturity securities	0	0
Loans held for sale	0	0
Loans receivable, net	0	0
Resell agreements	0	0
Accrued interest receivable	281	43
Financial liabilities:
FHLBNY advances	0	0
Subordinated debt, net	0	0
Accrued interest payable	0	0
Estimated Fair Value | Level 1 | Deposits payable on demand
Financial liabilities:
Deposits	0	0
Estimated Fair Value | Level 1 | Time deposits and brokered CDs
Financial liabilities:
Deposits	0	0
Estimated Fair Value | Level 1 | Other borrowings
Financial liabilities:
Other borrowings	0	0
Estimated Fair Value | Level 2
Financial assets:
Cash and cash equivalents	0	0
Held-to-maturity securities	571,999	575,418
Loans held for sale	0
Loans receivable, net	0	0
Resell agreements	0	0
Accrued interest receivable	13,111	12,645
Financial liabilities:
FHLBNY advances	8,818	4,381
Subordinated debt, net	56,456	56,790
Accrued interest payable	6,640	12,270
Estimated Fair Value | Level 2 | Deposits payable on demand
Financial liabilities:
Deposits	6,946,272	6,582,321
Estimated Fair Value | Level 2 | Time deposits and brokered CDs
Financial liabilities:
Deposits	357,684	428,116
Estimated Fair Value | Level 2 | Other borrowings
Financial liabilities:
Other borrowings	59,958	229,711
Estimated Fair Value | Level 3
Financial assets:
Cash and cash equivalents	0	0
Held-to-maturity securities	949,622	974,091
Loans held for sale	2,137	1,817
Loans receivable, net	4,026,693	4,029,142
Resell agreements	131,242	50,000
Accrued interest receivable	40,044	42,796
Financial liabilities:
FHLBNY advances	0	0
Subordinated debt, net	0	0
Accrued interest payable	0	0
Estimated Fair Value | Level 3 | Deposits payable on demand
Financial liabilities:
Deposits	0	0
Estimated Fair Value | Level 3 | Time deposits and brokered CDs
Financial liabilities:
Deposits	0	0
Estimated Fair Value | Level 3 | Other borrowings
Financial liabilities:
Other borrowings	$ 0	$ 0