Accumulated Other Comprehensive Income (''AOCI'') - Amount Reclassified from AOCI (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Amount Reclassified from AOCI
Interest income on taxable securities	$ 4,407		$ 1,944		$ 7,851	$ 3,672
Income tax expense	(6,147)		(2,950)		(11,277)	(7,273)
Net income	14,821	$ 12,866	8,813	$ 11,204	27,687	20,017
Amortization of unrealized gain on securities available-for-sale that were reclassified to securities held-to-maturity
Amount Reclassified from AOCI
Net of tax			9			18
Amortization of unrealized gain on securities available-for-sale that were reclassified to securities held-to-maturity | Amount Reclassified from AOCI
Amount Reclassified from AOCI
Interest income on taxable securities			13			26
Income tax expense			(4)			(8)
Net income			9			18
Defined Benefit Pension Plan Items
Amount Reclassified from AOCI
Net of tax	(73)		(148)		(146)	(261)
Defined Benefit Pension Plan Items | Amount Reclassified from AOCI
Amount Reclassified from AOCI
Other noninterest expense	(104)		(210)		(207)	(370)
Income tax benefit	31		62		61	109
Net of tax	(73)		(148)		(146)	(261)
Prior transition obligation | Amount Reclassified from AOCI
Amount Reclassified from AOCI
Other noninterest expense	10		1		21	2
Prior service cost | Amount Reclassified from AOCI
Amount Reclassified from AOCI
Other noninterest expense	(114)		(211)		(228)	(372)
Accumulated Other Comprehensive Income / (Loss)
Amount Reclassified from AOCI
Net of tax	(73)		(139)		(146)	(243)
Accumulated Other Comprehensive Income / (Loss) | Amount Reclassified from AOCI
Amount Reclassified from AOCI
Net of tax	$ (73)		$ (139)		$ (146)	$ (243)