Accumulated Other Comprehensive Income (Details 2) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net securities gains (losses)	$ 5	$ 6	$ 230	$ 18
Income tax expense	(2,715)	(2,579)	(8,634)	(8,000)
Unrealized gain (loss) on securities, net of tax	14,000	12,257	38,105	34,508
Change in funded status of post retirement benefits	383	303	1,171	910
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Unrealized gain (loss) on securities, net of tax	(379)	(299)	(998)	(897)
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	6	230	18
Income tax expense	(1)	(2)	(57)	(5)
Unrealized gain (loss) on securities, net of tax	4	4	173	13
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	109	86	305	258
Unrealized gain (loss) on securities, net of tax	(383)	(303)	(1,171)	(910)
Change in funded status of post retirement benefits	$ (492)	$ (389)	$ (1,476)	$ (1,168)