Securities - Amortized Cost and Fair Value, Held to Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 1,300,272	$ 1,324,072
Gross Unrealized Gains	91	17
Gross Unrealized Losses	(96,284)	(117,549)
Fair Value	1,204,079	1,206,540
Allowance for credit losses - held to maturity securities	(32)	(32)
Held to maturity securities, net of allowance for credit losses	1,300,240	1,324,040
Obligations of states and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	290,983	291,886
Gross Unrealized Gains	91	17
Gross Unrealized Losses	(38,774)	(48,325)
Fair Value	252,300	243,578
Residential mortgage backed securities:
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	415,243	423,315
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(25,330)	(30,706)
Fair Value	389,913	392,609
Other debt securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	61,068	62,875
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(3,272)	(4,266)
Fair Value	57,796	58,609
Government agency mortgage backed securities | Residential mortgage backed securities:
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	470,833	483,560
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(19,656)	(24,432)
Fair Value	451,177	459,128
Government agency mortgage backed securities | Commercial mortgage backed securities:
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	17,001	17,006
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(2,931)	(3,261)
Fair Value	14,070	13,745
Government agency collateralized mortgage obligations | Commercial mortgage backed securities:
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	45,144	45,430
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(6,321)	(6,559)
Fair Value	$ 38,823	$ 38,871