Comprehensive Income (Details) - Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sale of investment securities available-for-sale Net gains on sale investment securities	$ 7,005	$ 11,286	$ (6,444)
Sale of investment securities available-for-sale Income tax expense	1,847	2,923	(1,638)
Net interest (expense) income on swaps - Interest expense	1,600	(700)	(500)
Net interest (expense) income on swaps Income tax expense (benefit)	443	(190)	(130)
Net interest (expense) income on swaps	1,134	(487)	(334)
Total reclassification	3,944	7,642	(4,116)
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	29	(280)
Sale of investment securities available-for-sale Income tax expense	(6)	79
Sale of investment securities available-for-sale	23	(201)
Net interest (expense) income on swaps - Interest expense	(1,577)	677	464
Net interest (expense) income on swaps	(1,134)	487	334
Amortization of pension plan net actuarial losses - other components of net periodic pension expense	(301)	(358)	(359)
Amortization of pension plan net actuarial losses Income tax benefit	84	101	101
Amortization of pension plan net actuarial losses	(217)	(257)	(258)
Total reclassification	$ (1,328)	$ 29	$ 76