Investments - Revenue Bonds by Type (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Marketable Securities [Line Items]
Amortized Cost	$ 1,145,141
Investment securities available for sale	1,069,434
Amortized Cost (before ASU 2016-13)		$ 957,459
Investment securities available for sale (before ASU 2016-13)		973,314
States and Political Subdivisions [Member]
Marketable Securities [Line Items]
Amortized Cost	363,790
Investment securities available for sale	320,729
Amortized cost (available-for-sale securities and held-to-maturity securities)	413,114
Fair market value (available-for-sale securities and held-to-maturity securities)	363,118
Amortized Cost (before ASU 2016-13)		290,729
Investment securities available for sale (before ASU 2016-13)		304,268
Revenue Bonds [Member]
Marketable Securities [Line Items]
Amortized cost (available-for-sale securities and held-to-maturity securities)	56,212
Fair market value (available-for-sale securities and held-to-maturity securities)	49,434
Amortized Cost (before ASU 2016-13)		42,697
Investment securities available for sale (before ASU 2016-13)		44,586
Revenue Bonds [Member] \| Water [Member]
Marketable Securities [Line Items]
Amortized cost (available-for-sale securities and held-to-maturity securities)	22,741
Fair market value (available-for-sale securities and held-to-maturity securities)	20,064
Amortized Cost (before ASU 2016-13)		15,534
Investment securities available for sale (before ASU 2016-13)		16,220
Revenue Bonds [Member] \| Sewer [Member]
Marketable Securities [Line Items]
Amortized cost (available-for-sale securities and held-to-maturity securities)	7,091
Fair market value (available-for-sale securities and held-to-maturity securities)	6,144
Amortized Cost (before ASU 2016-13)		3,932
Investment securities available for sale (before ASU 2016-13)		4,165
Revenue Bonds [Member] \| Lease [Member]
Marketable Securities [Line Items]
Amortized cost (available-for-sale securities and held-to-maturity securities)	7,511
Fair market value (available-for-sale securities and held-to-maturity securities)	6,907
Amortized Cost (before ASU 2016-13)		6,556
Investment securities available for sale (before ASU 2016-13)		6,718
Revenue Bonds [Member] \| Sales Tax [Member]
Marketable Securities [Line Items]
Amortized cost (available-for-sale securities and held-to-maturity securities)	4,329
Fair market value (available-for-sale securities and held-to-maturity securities)	3,803
Revenue Bonds [Member] \| Intergovernmental Agreement [Member]
Marketable Securities [Line Items]
Amortized cost (available-for-sale securities and held-to-maturity securities)	2,836
Fair market value (available-for-sale securities and held-to-maturity securities)	2,600
Revenue Bonds [Member] \| Other Revenue Source [Member]
Marketable Securities [Line Items]
Amortized cost (available-for-sale securities and held-to-maturity securities)	11,704
Fair market value (available-for-sale securities and held-to-maturity securities)	$ 9,916
Amortized Cost (before ASU 2016-13)		16,675
Investment securities available for sale (before ASU 2016-13)		$ 17,483

Debt Securities, Excluding Accrued Interest, Amortized Cost

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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