Comprehensive Income (Details) - Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sale of investment securities available-for-sale Net gains on sale investment securities	$ 11,286	$ (6,444)	$ (1,350)
Sale of investment securities available-for-sale Income tax expense	2,923	(1,638)	(532)
Net interest income (expense) on swaps - Interest expense	(700)	(500)	400
Net interest income (expense) on swaps Income tax expense (benefit)	(190)	(130)	166
Net interest income (expense) on swaps	(487)	(334)	240
Total reclassification	7,642	(4,116)	(1,173)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sale of investment securities available-for-sale Net gains on sale investment securities	(280)		1,596
Sale of investment securities available-for-sale Income tax expense	79		(579)
Sale of investment securities available-for-sale	(201)		1,017
Net interest income (expense) on swaps - Interest expense	677	464	(406)
Net interest income (expense) on swaps	487	334	(240)
Amortization of pension plan net actuarial losses - other components of net periodic pension expense	(358)	(359)	(412)
Amortization of pension plan net actuarial losses Income tax benefit	101	101	169
Amortization of pension plan net actuarial losses	(257)	(258)	(243)
Total reclassification	$ 29	$ 76	$ 534