Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2015

Accounting Policies [Abstract]

Estimated Useful Lives Of Property And Equipment

Depreciation of property and equipment is calculated using the straight-line method over the estimated useful lives of the related assets. The following table provides the estimated useful lives by asset type: 

Structures	7 to 30 years
Revenue equipment	4 to 15 years
Other equipment	2 to 20 years
Leasehold improvements	Lesser of economic life or life of lease

Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]

	Year Ended December 31,
(In thousands)	2015		2014		2013
Acquisition of property and equipment by capital lease	$	3,552	$	—	$	—