Revenue Equipment On Operating Lease And Property, Plant, And Equipment (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 25, 2011	Dec. 26, 2010	Dec. 27, 2009
Revenue Equipment On Operating Lease And Property, Plant, And Equipment [Abstract]
Property, plant, and equipment under capital lease, gross	$ 2,200,000	$ 2,100,000
Property, plant, and equipment under capital lease, accumulated depreciation	1,500,000	1,500,000
Asset impairments	7,843,000
Depreciation expense	$ 24,500,000	$ 21,200,000	$ 18,800,000