Annual report pursuant to Section 13 and 15(d)

Significant Accounting Policies - (Estimated Useful Lives Of Property And Equipment) (Details)

v3.20.4
Significant Accounting Policies - (Estimated Useful Lives Of Property And Equipment) (Details)
12 Months Ended
Dec. 31, 2020
Leasehold Improvements [Member]  
Property Plant And Equipment [Line Items]  
Estimated useful lives of asset Lesser of economic life or life of lease
Minimum [Member] | Structures [Member]  
Property Plant And Equipment [Line Items]  
Estimated useful lives of asset, years 7 years
Minimum [Member] | Revenue Equipment [Member]  
Property Plant And Equipment [Line Items]  
Estimated useful lives of asset, years 4 years
Minimum [Member] | Other Equipment [Member]  
Property Plant And Equipment [Line Items]  
Estimated useful lives of asset, years 2 years
Maximum [Member] | Structures [Member]  
Property Plant And Equipment [Line Items]  
Estimated useful lives of asset, years 30 years
Maximum [Member] | Revenue Equipment [Member]  
Property Plant And Equipment [Line Items]  
Estimated useful lives of asset, years 15 years
Maximum [Member] | Other Equipment [Member]  
Property Plant And Equipment [Line Items]  
Estimated useful lives of asset, years 20 years