Revenue Equipment On Operating Lease And Property, Plant, And Equipment (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 30, 2012	Dec. 25, 2011	Dec. 26, 2010
Property, Plant and Equipment [Abstract]
Property, plant, and equipment under capital lease, gross	$ 2,000,000	$ 2,200,000
Property, plant, and equipment under capital lease, accumulated depreciation	1,500,000	1,500,000
Asset impairments	6,506,000	7,843,000	0
Depreciation expense	$ 20,300,000	$ 24,400,000	$ 21,000,000