Accumulated Other Comprehensive Income (Loss), Reclassifications out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Abstract]
Salaries and employee benefits	$ 12,134			$ 11,909			$ 32,837	$ 36,737
Income tax (benefit) expense	6,371			5,523			17,587	15,227
Net income	19,364	$ 17,871	$ 17,089	16,762	$ 14,433	$ 14,083	54,324	45,278
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Abstract]
Net income	265			(30)			754	227
Amortization of Pension and Postretirement Benefit Items [Member] | Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Abstract]
Income tax (benefit) expense	(93)			10			(265)	(80)
Net income	265			(30)			754	227
Amortization of Net Actuarial Gain [Member] | Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Abstract]
Salaries and employee benefits	280			137			784	534
Amortization of Prior Service Credit (Cost) [Member] | Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Abstract]
Salaries and employee benefits	$ 78			$ (177)			$ 235	$ (227)