FAIR VALUE OF ASSETS AND LIABILITIES - Balance Sheet Grouping (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Financial assets:
Cash and cash equivalents	$ 85,954	$ 194,719
Securities available for sale, at fair value	304,852	394,036
Securities held to maturity, at amortized cost	15,000
Federal Home Loan Bank stock	15,973	5,931
Securities held to maturity	14,451
Loans held for sale	18,805	45,642
Loans, net	4,152,733	3,562,356
Retirement plan annuities	14,511	14,174
Accrued interest receivable	12,746	10,624
Financial liabilities:
Deposits	3,883,110	3,682,649
Subordinated debt	34,254	34,159
Mortgagors' escrow accounts	9,842	8,459
Accrued interest payable	950	1,083
Carrying Amount
Financial assets:
Cash and cash equivalents	85,954	194,719
Securities available for sale, at fair value	304,852	394,036
Federal Home Loan Bank stock	15,973	5,931
Securities held to maturity	15,000
Loans held for sale	18,805	45,642
Loans, net	4,152,733	3,562,356
Retirement plan annuities	14,511	14,174
Accrued interest receivable	12,746	10,624
Financial liabilities:
Deposits	3,883,110	3,682,649
Borrowed funds	345,684	55,711
Subordinated debt	34,254	34,159
Mortgagors' escrow accounts	9,842	8,459
Accrued interest payable	950	1,083
Carrying Amount | Derivative loan commitments
Derivative commitments/agreements:
Assets	901	1,527
Liabilities	343	95
Carrying Amount | Interest rate management agreement
Derivative commitments/agreements:
Assets	8,669	1,663
Carrying Amount | Interest rate swaps
Derivative commitments/agreements:
Assets	29,243	18,874
Liabilities	29,243	19,214
Carrying Amount | Forward loan sale commitments
Derivative commitments/agreements:
Assets	1,334	56
Liabilities	16	94
Fair Value
Financial assets:
Cash and cash equivalents	85,954	194,719
Securities available for sale, at fair value	304,852	394,036
Securities held to maturity	14,451
Loans held for sale	18,805	45,642
Loans, net	4,067,780	3,558,934
Retirement plan annuities	14,511	14,174
Accrued interest receivable	12,746	10,624
Financial liabilities:
Deposits	3,861,090	3,683,465
Borrowed funds	344,611	55,765
Subordinated debt	31,054	35,790
Mortgagors' escrow accounts	9,842	8,459
Accrued interest payable	950	1,083
Fair Value | Derivative loan commitments
Derivative commitments/agreements:
Assets	901	1,527
Liabilities	343	95
Fair Value | Interest rate management agreement
Derivative commitments/agreements:
Assets	8,669	1,663
Fair Value | Interest rate swaps
Derivative commitments/agreements:
Assets	29,243	18,874
Liabilities	29,243	19,214
Fair Value | Forward loan sale commitments
Derivative commitments/agreements:
Assets	1,334	56
Liabilities	16	94
Fair Value | Level 1
Financial assets:
Cash and cash equivalents	85,954	194,719
Fair Value | Level 2
Financial assets:
Securities available for sale, at fair value	304,852	394,036
Securities held to maturity	14,451
Loans held for sale	18,805	45,642
Accrued interest receivable	12,746	10,624
Financial liabilities:
Borrowed funds	344,611	55,765
Accrued interest payable	950	1,083
Fair Value | Level 2 | Interest rate management agreement
Derivative commitments/agreements:
Assets	8,669	1,663
Fair Value | Level 2 | Interest rate swaps
Derivative commitments/agreements:
Assets	29,243	18,874
Liabilities	29,243	19,214
Fair Value | Level 3
Financial assets:
Loans, net	4,067,780	3,558,934
Retirement plan annuities	14,511	14,174
Financial liabilities:
Deposits	3,861,090	3,683,465
Subordinated debt	31,054	35,790
Mortgagors' escrow accounts	9,842	8,459
Fair Value | Level 3 | Derivative loan commitments
Derivative commitments/agreements:
Assets	901	1,527
Liabilities	343	95
Fair Value | Level 3 | Forward loan sale commitments
Derivative commitments/agreements:
Assets	1,334	56
Liabilities	$ 16	$ 94