Employee Benefit Plans (Details) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Pension Benefits
Components of net periodic benefit costs:
Interest cost	$ 80,000		$ 109,000	$ 256,000	$ 328,000
Expected return on plan assets	(187,000)		(195,000)	(577,000)	(586,000)
Amortization of net loss	35,000		19,000	101,000	58,000
Settlement charge	531,000		0	1,050,000	0
Net periodic benefit/cost	459,000		(67,000)	$ 830,000	(200,000)
Defined Benefit Plan, Benefit Obligation						$ 12,668,000
Defined Benefit Plan, Plan Assets, Amount						11,865,000
Defined Benefit Plan, Funded (Unfunded) Status of Plan						(803,000)
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate		3.12%		2.51%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets		7.50%		7.50%
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement				$ (1,172,000)
Defined Benefit Plan, Plan Assets, Payment for Settlement					0
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax	(531,000)			(531,000)		$ 5,068,000
Postretirement Benefits
Components of net periodic benefit costs:
Interest cost	1,000		1,000	2,000	3,000
Amortization of prior service cost	0		0	0	(1,000)
Amortization of net loss	(2,000)		(2,000)	(4,000)	(4,000)
Net periodic benefit/cost	(1,000)		$ (1,000)	$ (2,000)	$ (2,000)
Postretirement Benefits | Employees Hired before January 1, 2003
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Benefit based on highest average salary for number of consecutive years				5 years
Number of years for consecutive years calculation				10 years
Postretirement Benefits | Employees Hired on or after January 1, 2003
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Percent of annual salary to calculate benefit				2.00%
Before Settlement | Pension Benefits
Components of net periodic benefit costs:
Defined Benefit Plan, Benefit Obligation	12,854,000			$ 12,854,000
Defined Benefit Plan, Plan Assets, Amount	10,989,000			10,989,000
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(1,865,000)			(1,865,000)
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax	5,834,000			5,834,000
After Settlement
Components of net periodic benefit costs:
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax	5,303,000			5,303,000
After Settlement | Pension Benefits
Components of net periodic benefit costs:
Defined Benefit Plan, Benefit Obligation	11,682,000			11,682,000
Defined Benefit Plan, Plan Assets, Amount	9,817,000			9,817,000
Defined Benefit Plan, Funded (Unfunded) Status of Plan	$ (1,865,000)			$ (1,865,000)
Retirement prior to January 1, 1993 [Member]
Components of net periodic benefit costs:
Percent of healthcare costs paid	100.00%			100.00%