Investment Securities - Investments Classified by Contractual Maturity Date (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Available-for-sale investments, One year or less	$ 213,379
Available-for-sale investments, After 1 through 5 years	183,560
Available-for-sale investments, After 5 through 10 years	225,997
Available-for-sale investments, After ten years	589,762
Available-for-sale investments, Fair Value	$ 1,212,698	$ 1,218,985
Available-for-sale, Weighted average yield, One year or less (in hundredths)	1.56%
Available-for-sale , Weighted average yield,After 1 through 5 years (in hundredths)	2.67%
Available-for-sale, Weighted average yield,After 5 through 10 years (in hundredths)	2.00%
Available-for-sale , Weighted average yield,After ten years (in hundredths)	1.70%
Available-for-sale , Weighted average yield,Total (in hundredths)	1.87%
Available-for-sale, Full Tax-equivalent yield, One year or less (in hundredths)	1.59%
Available-for-sale, Full Tax-equivalent yield,After 1 through 5 years (in hundredths)	2.67%
Available-for-sale, Full Tax-equivalent yield, After 5 through 10 years (in hundredths)	1.94%
Available-for-sale, Full Tax-equivalent yield,After ten years (in hundredths)	1.71%
Available-for-sale, Full Tax-equivalent yield,Total (in hundredths)	1.87%
Held-to-maturity, Maturity [Abstract]
Held-to-maturity, One Year or less	$ 0
Held-to-maturity, After1 through 5 years	0
Held-to-maturity, After 5 through 10 years	0
Held-to-maturity, After ten years	2,979
Held-to-maturity	$ 2,979	2,954
Held To Maturity Weighted average yield, One year or less	0.00%
Held To Maturity Weighted average yield, After 1 through 5 years	0.00%
Held To Maturity Weighted average yield After 5 through 10 years	0.00%
Held To Maturity Weighted average yield After ten years	0.00%
Held To Maturity Weighted average yield ,Total	0.00%
Held To Maturity, Full tax-equivalent yield , One year or less	0.00%
Held To Maturity, Full tax-equivalent yield , After 1 through 5 years	0.00%
Held To Maturity, Full tax-equivalent yield , After 5 through 10 years	0.00%
Held To Maturity, Full tax-equivalent yield , After ten years	0.00%
Held To Maturity, Full tax-equivalent yield , Total	0.00%
U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Available-for-sale investments, One year or less	$ 172,917
Available-for-sale investments, After 1 through 5 years	40,859
Available-for-sale investments, After 5 through 10 years	9,769
Available-for-sale investments, After ten years	0
Available-for-sale investments, Fair Value	223,545	220,527
Obligations of States and Political Subdivisions
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Available-for-sale investments, One year or less	18,652
Available-for-sale investments, After 1 through 5 years	74,899
Available-for-sale investments, After 5 through 10 years	190,220
Available-for-sale investments, After ten years	1,226
Available-for-sale investments, Fair Value	284,997	287,698
Mortgage-backed Securities: GSE Residential
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Available-for-sale investments, One year or less	2,544
Available-for-sale investments, After 1 through 5 years	7,981
Available-for-sale investments, After 5 through 10 years	25,211
Available-for-sale investments, After ten years	588,536
Available-for-sale investments, Fair Value	624,272	627,880
Other Securities
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Available-for-sale investments, One year or less	19,266
Available-for-sale investments, After 1 through 5 years	59,821
Available-for-sale investments, After 5 through 10 years	797
Available-for-sale investments, After ten years	0
Available-for-sale investments, Fair Value	79,884	82,880
Other Investments
Held-to-maturity, Maturity [Abstract]
Held-to-maturity, One Year or less	0
Held-to-maturity, After1 through 5 years	0
Held-to-maturity, After 5 through 10 years	0
Held-to-maturity, After ten years	2,979
Held-to-maturity	$ 2,979	$ 2,954