FAIR VALUE OF ASSETS AND LIABILITIES - Balance Sheet Grouping (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financial assets:
Cash and cash equivalents	$ 393,441	$ 227,350
Securities available for sale, at fair value	291,008	290,151
Securities held to maturity	19,102	19,262
Federal Home Loan Bank stock	26,565	27,098
Loans held for sale	16,434	19,686
Loans, net	4,728,500	4,702,339
Retirement plan annuities	15,315	15,170
Accrued interest receivable	19,470	18,169
Financial liabilities:
Deposits	4,394,024	4,387,409
Mortgagors' escrow accounts	10,364	8,872
Accrued interest payable	7,302	5,251
Carrying Amount
Financial assets:
Cash and cash equivalents	393,441	227,350
Securities available for sale, at fair value	291,008	290,151
Securities held to maturity	19,724	19,796
Federal Home Loan Bank stock	26,565	27,098
Loans held for sale	16,434	19,686
Loans, net	4,728,500	4,702,339
Retirement plan annuities	15,315	15,170
Accrued interest receivable	19,470	18,169
Derivatives	31,006	28,824
Financial liabilities:
Deposits	4,394,024	4,387,409
Borrowed funds	754,380	303,000
Mortgagors' escrow accounts	10,364	8,872
Accrued interest payable	7,302	5,251
Derivatives	25,415	24,551
Fair Value
Financial assets:
Cash and cash equivalents	393,441	227,350
Securities available for sale, at fair value	291,008	290,151
Securities held to maturity	19,102	19,262
Loans held for sale	16,434	19,686
Loans, net	4,500,663	4,482,448
Retirement plan annuities	15,315	15,170
Accrued interest receivable	19,470	18,169
Derivatives	31,006	28,824
Financial liabilities:
Deposits	4,382,830	4,376,269
Borrowed funds	751,277	567,158
Mortgagors' escrow accounts	10,364	8,872
Accrued interest payable	7,302	5,251
Derivatives	25,415	24,551
Fair Value | Level 1
Financial assets:
Cash and cash equivalents	393,441	227,350
Fair Value | Level 2
Financial assets:
Securities available for sale, at fair value	291,008	290,151
Securities held to maturity	19,102	19,262
Loans held for sale	16,434	19,686
Accrued interest receivable	19,470	18,169
Derivatives	30,557	28,340
Financial liabilities:
Borrowed funds	751,277	567,158
Accrued interest payable	7,302	5,251
Derivatives	25,365	24,100
Fair Value | Level 3
Financial assets:
Loans, net	4,500,663	4,482,448
Retirement plan annuities	15,315	15,170
Derivatives	449	484
Financial liabilities:
Deposits	4,382,830	4,376,269
Mortgagors' escrow accounts	10,364	8,872
Derivatives	$ 50	$ 451