Loan Portfolio and Allowance for Credit Losses, Based on Impairment Review Method (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Ending allowance balance attributable to loans [Abstract]
Individually evaluated for impairment	$ 0	$ 0	$ 0
Collectively evaluated for impairment	49,220	48,578
Total ending allowance balance	49,220	48,578	46,685	$ 46,032
Loans [Abstract]
Individually evaluated for impairment	24,847	24,729
Collectively evaluated for impairment	4,980,659	4,978,150
Total loans	5,005,506	5,002,879
Commercial Loans [Member]
Ending allowance balance attributable to loans [Abstract]
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	2,742	2,735
Total ending allowance balance	2,742	2,735	2,708	2,596
Loans [Abstract]
Individually evaluated for impairment	952	957
Collectively evaluated for impairment	278,140	272,558
Total loans	279,092	273,515
1 to 4 Family Residential Real Estate [Member]
Ending allowance balance attributable to loans [Abstract]
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	46,295	45,625
Total ending allowance balance	46,295	45,625	43,766	43,271
Loans [Abstract]
Individually evaluated for impairment	23,769	23,628
Collectively evaluated for impairment	4,686,479	4,688,850
Total loans	4,710,248	4,712,478
Installment Loans [Member]
Ending allowance balance attributable to loans [Abstract]
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	183	218
Total ending allowance balance	183	218	$ 211	$ 165
Loans [Abstract]
Individually evaluated for impairment	126	144
Collectively evaluated for impairment	16,040	16,742
Total loans	$ 16,166	$ 16,886