Accumulated Other Comprehensive Income (Loss), Accumulated Other Comprehensive Income (Loss) Balances, Net of Tax (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance	$ 614,703	$ 599,987	$ 592,895	$ 601,128	$ 599,987	$ 601,128
Other comprehensive income (loss) - before reclassifications	(2,755)		(6,829)		1,146	(21,080)
Amount reclassified from accumulated other comprehensive (loss) income	(82)		(224)		(164)	(489)
Other comprehensive (loss) gain, net of tax	(2,837)	3,819	(7,053)	(14,516)	982	(21,569)
Balance	621,389	614,703	594,632	592,895	621,389	594,632
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance	(23,375)	(27,194)	(2,369)	12,147	(27,194)	12,147
Other comprehensive (loss) gain, net of tax	(2,837)	3,819	(7,053)	(14,516)
Balance	(26,212)	(23,375)	(9,422)	(2,369)	(26,212)	(9,422)
Net Unrealized Holding Gain (Loss) on Securities Available for Sale, Net of Tax [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance	(28,370)	(32,271)	(14,277)	(26)	(32,271)	(26)
Other comprehensive income (loss) - before reclassifications	(2,755)		(6,829)		1,146	(21,080)
Amount reclassified from accumulated other comprehensive (loss) income	0		0		0	0
Other comprehensive (loss) gain, net of tax	(2,755)		(6,829)		1,146	(21,080)
Balance	(31,125)	(28,370)	(21,106)	(14,277)	(31,125)	(21,106)
Net Change in Overfunded Position in Pension and Postretirement Plans Arising During the Year, Net of Tax [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance	7,588	7,588	13,706	13,706	7,588	13,706
Other comprehensive income (loss) - before reclassifications	0		0		0	0
Amount reclassified from accumulated other comprehensive (loss) income	0		0		0	0
Other comprehensive (loss) gain, net of tax	0		0		0	0
Balance	7,588	7,588	13,706	13,706	7,588	13,706
Net Change in Net Actuarial Gain and Prior Service Cost (Credit) on Pension and Postretirement Benefit Plans, Net of Tax [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance	(2,593)	(2,511)	(1,798)	(1,533)	(2,511)	(1,533)
Other comprehensive income (loss) - before reclassifications	0		0		0	0
Amount reclassified from accumulated other comprehensive (loss) income	(82)		(224)		(164)	(489)
Other comprehensive (loss) gain, net of tax	(82)		(224)		(164)	(489)
Balance	$ (2,675)	$ (2,593)	$ (2,022)	$ (1,798)	$ (2,675)	$ (2,022)