Pensions and Other Postretirement Benefit Plans (Schedule of Pension Plans with Projected Benefit Obligation and Accumulated Benefit Obligation in Excess of Plan Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Pension Plan with Project Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligation	$ 42,703	$ 137,123
Fair value of plan assets	4,815	100,330
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Accumulated benefit obligation	40,133	134,737
Fair value of plan assets	$ 4,815	$ 100,330