Description of Business and Summary of Significant Accounting Policies (Summary Of Property And Equipment) (Details)	6 Months Ended
	Jun. 30, 2021
Computer and Other Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Minimum [Member] | Building And Building Under Finance Lease [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	15 years
Minimum [Member] | Machinery, Equipment and Vehicles [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Minimum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Minimum [Member] | Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Minimum [Member] | Assets Held Under Capital Leases [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Maximum [Member] | Building And Building Under Finance Lease [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	20 years
Maximum [Member] | Machinery, Equipment and Vehicles [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years
Maximum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years
Maximum [Member] | Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	15 years
Maximum [Member] | Assets Held Under Capital Leases [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years