Leases (Summary Of Weighted-Average Lease Term And Discount Rate) (Details)	Mar. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Finance leases, Weighted Average Lease Term	9 months 18 days	9 months 18 days
Operating leases, Weighted Average Lease Term	3 years 7 months 6 days	3 years 9 months 18 days
Finance leases, Weighted Average Discount Rate	5.56%	5.56%
Operating leases, Weighted Average Discount Rate	5.06%	5.06%