Fair Value of Assets and Liabilities - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($)	Mar. 31, 2024	Dec. 31, 2023
Available-for-sale securities:
Total available-for-sale securities	$ 1,139,427,000	$ 1,171,572,000
Equity securities, at fair value	4,298,000	4,074,000
U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies
Available-for-sale securities:
Total available-for-sale securities	207,320,000	211,656,000
Obligations of States and Political Subdivisions
Available-for-sale securities:
Total available-for-sale securities	282,570,000	288,616,000
Mortgage-backed Securities
Available-for-sale securities:
Total available-for-sale securities	581,004,000	602,300,000
Other Securities
Available-for-sale securities:
Total available-for-sale securities	68,533,000	69,000,000
Fair Value, Recurring
Available-for-sale securities:
Total available-for-sale securities	1,139,427,000	1,171,572,000
Equity securities, at fair value	4,298,000	4,074,000
Loans held for sale, fair value	4,817,000	4,980,000
Derivative assets: interest rate swaps	3,539,000	3,166,000
Total assets	1,152,081,000	1,183,792,000
Derivative liabilities: interest swaps	2,435,000	2,217,000
Fair Value, Recurring | U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies
Available-for-sale securities:
Total available-for-sale securities	207,320,000	211,656,000
Fair Value, Recurring | Obligations of States and Political Subdivisions
Available-for-sale securities:
Total available-for-sale securities	282,570,000	288,616,000
Fair Value, Recurring | Mortgage-backed Securities
Available-for-sale securities:
Total available-for-sale securities	581,004,000	602,300,000
Fair Value, Recurring | Other Securities
Available-for-sale securities:
Total available-for-sale securities	68,533,000	69,000,000
Quoted Prices in Active Markets for Identical Assets (Level 1)
Available-for-sale securities:
Total available-for-sale securities	0	0
Equity securities, at fair value	4,298,000	4,074,000
Loans held for sale, fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring
Available-for-sale securities:
Total available-for-sale securities	0	0
Equity securities, at fair value	4,298,000	4,074,000
Loans held for sale, fair value	0	0
Derivative assets: interest rate swaps	0	0
Total assets	4,298,000	4,074,000
Derivative liabilities: interest swaps	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring | U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies
Available-for-sale securities:
Total available-for-sale securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring | Obligations of States and Political Subdivisions
Available-for-sale securities:
Total available-for-sale securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring | Mortgage-backed Securities
Available-for-sale securities:
Total available-for-sale securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Recurring | Other Securities
Available-for-sale securities:
Total available-for-sale securities	0	0
Significant Other Observable Inputs (Level 2)
Available-for-sale securities:
Total available-for-sale securities	1,133,462,000	1,165,409,000
Equity securities, at fair value	0	0
Loans held for sale, fair value	4,817,000	4,980,000
Significant Other Observable Inputs (Level 2) | Fair Value, Recurring
Available-for-sale securities:
Total available-for-sale securities	1,133,462,000	1,165,409,000
Equity securities, at fair value	0	0
Loans held for sale, fair value	4,817,000	4,980,000
Derivative assets: interest rate swaps	3,539,000	3,166,000
Total assets	1,141,818,000	1,173,555,000
Derivative liabilities: interest swaps	2,435,000	2,217,000
Significant Other Observable Inputs (Level 2) | Fair Value, Recurring | U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies
Available-for-sale securities:
Total available-for-sale securities	207,320,000	211,656,000
Significant Other Observable Inputs (Level 2) | Fair Value, Recurring | Obligations of States and Political Subdivisions
Available-for-sale securities:
Total available-for-sale securities	282,570,000	288,616,000
Significant Other Observable Inputs (Level 2) | Fair Value, Recurring | Mortgage-backed Securities
Available-for-sale securities:
Total available-for-sale securities	581,004,000	602,300,000
Significant Other Observable Inputs (Level 2) | Fair Value, Recurring | Other Securities
Available-for-sale securities:
Total available-for-sale securities	62,568,000	62,837,000
Significant Unobservable Inputs (Level 3)
Available-for-sale securities:
Total available-for-sale securities	5,965,000	6,163,000
Equity securities, at fair value	0	0
Loans held for sale, fair value	0	0
Significant Unobservable Inputs (Level 3) | Fair Value, Recurring
Available-for-sale securities:
Total available-for-sale securities	5,965,000	6,163,000
Equity securities, at fair value	0	0
Loans held for sale, fair value	0	0
Derivative assets: interest rate swaps	0	0
Total assets	5,965,000	6,163,000
Derivative liabilities: interest swaps	0	0
Significant Unobservable Inputs (Level 3) | Fair Value, Recurring | U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies
Available-for-sale securities:
Total available-for-sale securities	0	0
Significant Unobservable Inputs (Level 3) | Fair Value, Recurring | Obligations of States and Political Subdivisions
Available-for-sale securities:
Total available-for-sale securities	0	0
Significant Unobservable Inputs (Level 3) | Fair Value, Recurring | Mortgage-backed Securities
Available-for-sale securities:
Total available-for-sale securities	0	0
Significant Unobservable Inputs (Level 3) | Fair Value, Recurring | Other Securities
Available-for-sale securities:
Total available-for-sale securities	$ 5,965,000	$ 6,163,000