Annual report pursuant to Section 13 and 15(d)

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

v2.4.0.6
Significant Accounting Policies (Estimated Useful Lives Of Property And Equipment) (Details)
12 Months Ended
Dec. 31, 2011
years
Structures [Member]
 
Significant Accounting Policies [Line Items]  
Estimated minimum useful lives of asset, years 7
Estimated maximum useful lives of asset, years 30
Revenue Equipment [Member]
 
Significant Accounting Policies [Line Items]  
Estimated minimum useful lives of asset, years 4
Estimated maximum useful lives of asset, years 15
Other Equipment [Member]
 
Significant Accounting Policies [Line Items]  
Estimated minimum useful lives of asset, years 2
Estimated maximum useful lives of asset, years 20
Leasehold Improvements [Member]
 
Significant Accounting Policies [Line Items]  
Estimated useful lives of assets Lesser of economic life or life of lease