Investment Securities - Amortized Cost of Investment Securities Held to Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 2,180,047	$ 1,227,668
Aaa
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	150,869
Aa1
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	152,666
Aa2
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	175,755
Aa3
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	130,640
A1
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	88,281
A2
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	27,364
A3
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	10,108
Baa2
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	265
Non-rated
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	1,444,099
State and municipal
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	1,057,301	$ 619,927
State and municipal | Aaa
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	90,290
State and municipal | Aa1
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	152,666
State and municipal | Aa2
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	175,755
State and municipal | Aa3
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	130,640
State and municipal | A1
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	88,281
State and municipal | A2
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	27,364
State and municipal | A3
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	10,108
State and municipal | Baa2
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	265
State and municipal | Non-rated
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	381,932
Other
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	1,122,746
Other | Aaa
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	60,579
Other | Aa1
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	0
Other | Aa2
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	0
Other | Aa3
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	0
Other | A1
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	0
Other | A2
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	0
Other | A3
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	0
Other | Baa2
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	0
Other | Non-rated
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 1,062,167