Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive income (loss)	$ (314,034)	$ (341,975)
Unrealized Loss on Securities Available for Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive income (loss)	(408,731)	(444,063)
Deferred tax asset	94,622	102,046
Total accumulated other comprehensive income (loss)	(314,109)	(342,017)
Postretirement Plans Asset (Liability)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive income (loss)	98	54
Deferred tax asset	(23)	(12)
Total accumulated other comprehensive income (loss)	$ 75	$ 42