Securities - Amortized Cost and Fair Value, Held to Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 1,273,076	$ 1,324,072
Gross Unrealized Gains	23	17
Gross Unrealized Losses	(119,558)	(117,549)
Fair Value	1,153,541	1,206,540
Allowance for credit losses - held to maturity securities	(32)	(32)
Held to maturity securities, net of allowance for credit losses	1,273,044	1,324,040
Obligations of states and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	289,949	291,886
Gross Unrealized Gains	23	17
Gross Unrealized Losses	(42,782)	(48,325)
Fair Value	247,190	243,578
Residential mortgage backed securities:
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	405,793	423,315
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(35,372)	(30,706)
Fair Value	370,421	392,609
Other debt securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	60,227	62,875
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(5,058)	(4,266)
Fair Value	55,169	58,609
Government agency mortgage backed securities | Residential mortgage backed securities:
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	455,199	483,560
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(25,797)	(24,432)
Fair Value	429,402	459,128
Government agency mortgage backed securities | Commercial mortgage backed securities:
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	16,995	17,006
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(3,231)	(3,261)
Fair Value	13,764	13,745
Government agency collateralized mortgage obligations | Commercial mortgage backed securities:
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	44,913	45,430
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(7,318)	(6,559)
Fair Value	$ 37,595	$ 38,871