Contingencies (Schedule of Changes in Claims) (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021 USD ($) claim	Dec. 31, 2020 USD ($) claim	Dec. 31, 2019 USD ($) claim	Dec. 31, 2018 USD ($) claim	Dec. 31, 2017 USD ($) claim	Dec. 31, 2016 USD ($) claim
Loss Contingencies [Line Items]
Closing Number of Claims	3,617
Asbestos Issue
Loss Contingencies [Line Items]
Opening Number of Claims	3,615	3,708	3,684	3,730	3,745	3,791
Claims Dismissed, Settled, or Resolved	5	152	51	152	105	148
New Claims	7	59	75	106	90	102
Closing Number of Claims	3,617	3,615	3,708	3,684	3,730	3,745
Amounts Paid (thousands) to Settle or Resolve | $	$ 0	$ 57	$ 25	$ 100	$ 55	$ 758