Fair Value - Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) - USD ($)	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Assets
Securities available-for-sale	$ 404,474,000	$ 442,636,000
Securities held-to-maturity	542,858,000	564,127,000
FHLB stock, FRB stock, and other investments	32,544,000	32,540,000
Liabilities
Subordinated debt	39,539,000	39,502,000
Allowance for credit losses on loans	47,888,000	47,958,000	$ 47,273,000	$ 47,512,000
Carrying Amounts
Assets
Cash and cash equivalents	541,359,000	408,129,000
Securities available-for-sale	404,474,000	442,636,000
Securities held-to-maturity	636,249,000	650,565,000
Loans (including loans held-for-sale)	3,338,048,000	3,352,583,000
FHLB stock, FRB stock, and other investments	32,544,000	32,540,000
Accrued interest receivable	16,246,000	14,959,000
I/O strips receivables	110,000	117,000
Liabilities
Time deposits	488,112,000	469,472,000
Other deposits	3,956,548,000	3,908,986,000
Subordinated debt	39,539,000	39,502,000
Accrued interest payable	5,296,000	4,688,000
Balance
Assets
Cash and cash equivalents	541,359,000	408,129,000
Securities available-for-sale	404,474,000	442,636,000
Securities held-to-maturity	542,858,000	564,127,000
Loans (including loans held-for-sale)	3,144,819,000	3,174,717,000
Accrued interest receivable	16,246,000	14,959,000
I/O strips receivables	110,000	117,000
Liabilities
Time deposits	491,943,000	471,693,000
Other deposits	3,956,548,000	3,908,986,000
Subordinated debt	32,339,000	31,902,000
Accrued interest payable	5,296,000	4,698,000
Balance | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Cash and cash equivalents	541,359,000	408,129,000
Securities available-for-sale	347,453,000	382,369,000
Accrued interest receivable	1,592,000	1,255,000
Balance | Significant Other Observable Inputs (Level 2)
Assets
Securities available-for-sale	57,021,000	60,267,000
Securities held-to-maturity	542,858,000	564,127,000
Loans (including loans held-for-sale)	1,946,000	2,205,000
Accrued interest receivable	2,482,000	1,764,000
I/O strips receivables	110,000	117,000
Liabilities
Time deposits	491,943,000	471,693,000
Other deposits	3,956,548,000	3,908,986,000
Subordinated debt	32,339,000	31,902,000
Accrued interest payable	5,296,000	4,698,000
Balance | Significant Unobservable Inputs (Level 3)
Assets
Loans (including loans held-for-sale)	3,142,873,000	3,172,512,000
Accrued interest receivable	$ 12,172,000	$ 11,940,000