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Investment Securities - Amortized Cost of Investment Securities Held to Maturity (Details) - USD ($) $ in Thousands | Dec. 31, 2021 | Dec. 31, 2020
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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 |

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