Investment Securities - Investments Classified by Contractual Maturity Date (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Available-for-sale investments, One year or less	$ 218,379
Available-for-sale investments, After 1 through 5 years	331,447
Available-for-sale investments, After 5 through 10 years	789,972
Available-for-sale investments, After ten years	10,150
Available-for-sale investments, Fair Value	$ 1,349,948	$ 1,421,422
Available-for-sale, Weighted average yield, One year or less (in hundredths)	1.54%
Available-for-sale , Weighted average yield,After 1 through 5 years (in hundredths)	2.46%
Available-for-sale, Weighted average yield,After 5 through 10 years (in hundredths)	1.77%
Available-for-sale , Weighted average yield,After ten years (in hundredths)	1.69%
Available-for-sale , Weighted average yield,Total (in hundredths)	1.89%
Available-for-sale, Full Tax-equivalent yield, One year or less (in hundredths)	1.65%
Available-for-sale, Full Tax-equivalent yield,After 1 through 5 years (in hundredths)	2.75%
Available-for-sale, Full Tax-equivalent yield, After 5 through 10 years (in hundredths)	1.95%
Available-for-sale, Full Tax-equivalent yield,After ten years (in hundredths)	1.82%
Available-for-sale, Full Tax-equivalent yield,Total (in hundredths)	2.09%
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	2,972
Held-to-maturity	$ 2,972	7,030
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	$ 170,756
Available-for-sale investments, After 1 through 5 years	56,145
Available-for-sale investments, After 5 through 10 years	9,946
Available-for-sale investments, After ten years	0
Available-for-sale investments, Fair Value	236,847	203,815
Held-to-maturity, Maturity [Abstract]
Held-to-maturity		5,001
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	22,218
Available-for-sale investments, After 1 through 5 years	95,449
Available-for-sale investments, After 5 through 10 years	209,021
Available-for-sale investments, After ten years	1,134
Available-for-sale investments, Fair Value	327,822	395,457
Mortgage-backed Securities: GSE Residential
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Available-for-sale investments, One year or less	6,114
Available-for-sale investments, After 1 through 5 years	113,107
Available-for-sale investments, After 5 through 10 years	570,106
Available-for-sale investments, After ten years	9,016
Available-for-sale investments, Fair Value	698,343	791,038
Other Securities
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
Available-for-sale investments, One year or less	19,291
Available-for-sale investments, After 1 through 5 years	66,746
Available-for-sale investments, After 5 through 10 years	899
Available-for-sale investments, After ten years	0
Available-for-sale investments, Fair Value	86,936	31,112
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	2,972
Held-to-maturity	$ 2,972	$ 2,029