Accumulated Other Comprehensive Income (Details 2) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net securities gains (losses)	$ 5	$ 5	$ 111	$ 230
Income tax expense	(4,063)	(2,715)	(11,447)	(8,634)
Net Income	16,098	14,000	45,589	38,105
Change in funded status of post retirement benefits	471	383	1,415	1,171
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net Income	(467)	(379)	(1,332)	(998)
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net securities gains (losses)	5	5	111	230
Income tax expense	(1)	(1)	(28)	(57)
Net Income	4	4	83	173
Accumulated Defined Benefit Plans Adjustment [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income tax expense	47	109	139	305
Net Income	(471)	(383)	(1,415)	(1,171)
Change in funded status of post retirement benefits	$ (518)	$ (492)	$ (1,554)	$ (1,476)