Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance beginning	$ 237,047	$ 222,972	$ 228,048	$ 218,985
Before reclassifications	286	829	3,656	5,482
Reclassifications	0	16	(175)	29
Balance ending	238,585	225,492	238,585	225,492
Total [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance beginning	3,868		673
Balance ending	4,154	792	4,154	792
Unrealized Gains and Losses on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Before reclassifications	286	829	3,655	5,482
Reclassifications	0	16	(175)	29
Balance ending	4,337		4,337
Changes in Pension Plan Assets and Benefit Obligations [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Before reclassifications	0	0	1	0
Reclassifications	0	0	0	0
Balance ending	(183)		(183)
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Total [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance beginning	3,868	(53)	673	(4,719)
Balance ending		792		792
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Unrealized Gains and Losses on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance beginning	4,051	35	857	(4,631)
Balance ending		880		880
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Changes in Pension Plan Assets and Benefit Obligations [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance beginning	$ (183)	(88)	$ (184)	(88)
Balance ending		$ (88)		$ (88)