Accumulated Other Comprehensive Income (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net securities gains (losses)	$ 31	$ 16	$ 225	$ 12
Income tax expense	(2,899)	(3,204)	(5,919)	(5,421)
Unrealized gain (loss) on securities, net of tax	11,924	12,569	24,105	22,251
Change in funded status of post retirement benefits	384	304	788	607
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	(361)	(292)	(619)	(598)
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)	31	16	225	12
Income tax expense	(8)	(4)	(56)	(3)
Unrealized gain (loss) on securities, net of tax	23	12	169	9
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	108	86	196	172
Unrealized gain (loss) on securities, net of tax	(384)	(304)	(788)	(607)
Change in funded status of post retirement benefits	$ (492)	$ (390)	$ (984)	$ (779)