Securities (Narrative) (Details)	1 Months Ended	3 Months Ended
	Apr. 30, 2024 USD ($)	Mar. 31, 2024 USD ($) security $ / shares shares	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2023 USD ($) security
Debt and Equity Securities, FV-NI [Line Items]
Private mortgage-backed security fair value		$ 700,000			$ 700,000
Debt securities, available-for-sale and held-to-maturity, number of positions | security		651			657
Number of securities held in an unrealized loss position | security		631			632
Investment securities, pledged as collateral for public deposits		$ 910,800,000			$ 971,300,000
Proceeds from sales of securities available for sale		0	$ 111,863,000	$ 5,200,000
Losses on calls of securities, net		(975,000)	$ 0	$ (975,200)
FHLB stock and FRB stock, cost		41,400,000			54,500,000
FHLB, cost		8,500,000			21,700,000
FRB stock		32,900,000			32,800,000
Collateral For FRB Borrowings
Debt and Equity Securities, FV-NI [Line Items]
Investment securities, pledged as collateral for public deposits		$ 668,900,000			$ 679,000,000
Common Class B | Forecast
Debt and Equity Securities, FV-NI [Line Items]
Gain on shares sold	$ 4,500,000
Visa, Inc | Common Class B
Debt and Equity Securities, FV-NI [Line Items]
Stock owned (in shares) | shares		12,356
Carrying value of shares		$ 0
Visa, Inc | Common Class A
Debt and Equity Securities, FV-NI [Line Items]
Conversion price (in dollars per share) | $ / shares		$ 1.5875
Conversion of stock (in shares) | shares		19,615