Pension Plans and Postretirement Benefit Plan (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Pension Benefits
Net periodic benefit cost for pension plans and the postretirement benefit plan
Service Cost	$ 0	$ 0	$ 0	$ 0
Interest Cost	900	1,093	1,800	2,187
Expected Return on Plan Assets	(1,258)	(1,249)	(2,516)	(2,498)
Amortization of Prior Service Credit	0	0	0	0
Amortization of Net Actuarial Losses (Gains)	571	484	1,141	968
Net Periodic Benefit Cost	213	328	425	657
Employer Contributions			200
Estimated Future Employer Contributions in Current Fiscal Year	400		400
Postretirement Benefits
Net periodic benefit cost for pension plans and the postretirement benefit plan
Service Cost	152	117	303	235
Interest Cost	231	257	462	515
Expected Return on Plan Assets	0	0	0	0
Amortization of Prior Service Credit	(62)	(72)	(123)	(144)
Amortization of Net Actuarial Losses (Gains)	0	(78)	0	(156)
Net Periodic Benefit Cost	321	$ 224	642	$ 450
Employer Contributions			500
Estimated Future Employer Contributions in Current Fiscal Year	$ 1,000		$ 1,000