Comprehensive Income - Reclassification out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Salaries and Employee Benefits	$ 10,408	$ 10,015	$ 31,003	$ 29,061
Total before Tax	13,839	12,685	35,734	34,809
Provision for income taxes	(2,793)	(2,618)	(7,402)	(7,074)
Net Income	11,046	10,067	28,332	27,735
Amounts Reclassified from Accumulated Other Comprehensive Income | Amortization of Defined Benefit Pension, Prior-Service Costs
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Salaries and Employee Benefits	(53)	(56)	(159)	(169)
Amounts Reclassified from Accumulated Other Comprehensive Income | Amortization of Defined Benefit Pension, Actuarial Loss
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Salaries and Employee Benefits	(57)	(172)	(171)	(514)
Amounts Reclassified from Accumulated Other Comprehensive Income | Accumulated Defined Benefit Plans Adjustment
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Total before Tax	(110)	(228)	(330)	(683)
Provision for income taxes	29	59	86	175
Net Income	$ (81)	$ (169)	$ (244)	$ (508)