Fair Value Measurements, Assets and Liabilities on a Nonrecurring Basis (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Readily Available Market Prices
Loans, net of allowance for credit losses
Agricultural	$ 0	$ 0
Commercial and financial	0	0
Real Estate [Abstract]
Construction, land development and commercial	0	0
Mortgage, farmland	0	0
Mortgage, 1 to 4 family first liens	0	0
Mortgage, 1 to 4 family junior liens	0	0
Mortgage, multi-family	0	0
Mortgage, commercial	0	0
Loans to individuals	0	0
Total financial instrument assets	488,594	481,972
Observable Market Prices
Loans, net of allowance for credit losses
Agricultural	0	0
Commercial and financial	0	0
Real Estate [Abstract]
Construction, land development and commercial	0	0
Mortgage, farmland	0	0
Mortgage, 1 to 4 family first liens	0	0
Mortgage, 1 to 4 family junior liens	0	0
Mortgage, multi-family	0	0
Mortgage, commercial	0	0
Loans to individuals	0	0
Total financial instrument assets	429,475	394,486
Company Determined Market Prices
Loans, net of allowance for credit losses
Agricultural	107,011	112,421
Commercial and financial	299,816	294,021
Real Estate [Abstract]
Construction, land development and commercial	277,522	299,846
Mortgage, farmland	263,138	259,969
Mortgage, 1 to 4 family first liens	1,101,057	1,114,737
Mortgage, 1 to 4 family junior liens	134,477	135,529
Mortgage, multi-family	441,786	435,222
Mortgage, commercial	416,749	386,712
Loans to individuals	35,133	37,600
Total financial instrument assets	3,202,853	3,198,971
Nonrecurring Basis
Loans, net of allowance for credit losses
Agricultural	1,676	0
Commercial and financial	99	1,044
Real Estate [Abstract]
Construction, 1 to 4 family residential	0	5,235
Construction, land development and commercial	0	2,755
Mortgage, farmland	0	0
Mortgage, 1 to 4 family first liens	792	1,518
Mortgage, 1 to 4 family junior liens	0	0
Mortgage, multi-family	55	0
Mortgage, commercial	538	1,911
Loans to individuals	0	0
Foreclosed assets	0	0
Total financial instrument assets	3,160	12,463
Total Losses	190	2,752
Nonrecurring Basis | Agricultural
Real Estate [Abstract]
Total Losses	0	419
Nonrecurring Basis | Commercial and financial
Real Estate [Abstract]
Total Losses	0	26
Nonrecurring Basis | Construction, 1 to 4 family residential
Real Estate [Abstract]
Total Losses	61	1,148
Nonrecurring Basis | Construction, land development and commercial
Real Estate [Abstract]
Total Losses	0	447
Nonrecurring Basis | Real Estate: Mortgage, farmland
Real Estate [Abstract]
Total Losses	0	0
Nonrecurring Basis | Mortgage, 1 to 4 family first liens
Real Estate [Abstract]
Total Losses	104	(33)
Nonrecurring Basis | Mortgage, 1 to 4 family junior liens
Real Estate [Abstract]
Total Losses	25	0
Nonrecurring Basis | Mortgage, multi-family
Real Estate [Abstract]
Total Losses	0	20
Nonrecurring Basis | Mortgage, commercial
Real Estate [Abstract]
Total Losses	0	725
Nonrecurring Basis | Loans to individuals
Real Estate [Abstract]
Total Losses	0	0
Nonrecurring Basis | Foreclosed assets
Real Estate [Abstract]
Total Losses	0	0
Nonrecurring Basis | Readily Available Market Prices
Loans, net of allowance for credit losses
Agricultural	0	0
Commercial and financial	0	0
Real Estate [Abstract]
Construction, 1 to 4 family residential	0	0
Construction, land development and commercial	0	0
Mortgage, farmland	0	0
Mortgage, 1 to 4 family first liens	0	0
Mortgage, 1 to 4 family junior liens	0	0
Mortgage, multi-family	0	0
Mortgage, commercial	0	0
Loans to individuals	0	0
Foreclosed assets	0	0
Total financial instrument assets	0	0
Nonrecurring Basis | Observable Market Prices
Loans, net of allowance for credit losses
Agricultural	0	0
Commercial and financial	0	0
Real Estate [Abstract]
Construction, 1 to 4 family residential	0	0
Construction, land development and commercial	0	0
Mortgage, farmland	0	0
Mortgage, 1 to 4 family first liens	0	0
Mortgage, 1 to 4 family junior liens	0	0
Mortgage, multi-family	0	0
Mortgage, commercial	0	0
Loans to individuals	0	0
Foreclosed assets	0	0
Total financial instrument assets	0	0
Nonrecurring Basis | Company Determined Market Prices
Loans, net of allowance for credit losses
Agricultural	1,676	0
Commercial and financial	99	1,044
Real Estate [Abstract]
Construction, 1 to 4 family residential		5,235
Construction, land development and commercial		2,755
Mortgage, farmland		0
Mortgage, 1 to 4 family first liens	792	1,518
Mortgage, 1 to 4 family junior liens		0
Mortgage, multi-family	55	0
Mortgage, commercial	538	1,911
Loans to individuals	0	0
Foreclosed assets	0	0
Total financial instrument assets	$ 3,160	$ 12,463