Annual report pursuant to Section 13 and 15(d)

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

v3.10.0.1
Significant Accounting Policies (Estimated Useful Lives Of Property And Equipment) (Details)
12 Months Ended
Dec. 31, 2018
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