Segment Information (Information Regarding Reportable Business Segments) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 24, 2011	Jun. 25, 2011	Mar. 26, 2011	Dec. 25, 2010	Sep. 25, 2010	Jun. 26, 2010	Mar. 27, 2010	Dec. 31, 2011 Cus	Dec. 25, 2010 Cus	Dec. 26, 2009 Cus
Segment Reporting Information [Line Items]
External revenue	$ 717,522,000	$ 684,013,000	$ 675,561,000	$ 571,986,000	$ 587,535,000	$ 622,826,000	$ 641,721,000	$ 548,088,000	$ 2,649,082,000	$ 2,400,170,000	$ 2,008,796,000
Internal revenue									27,544,000	27,535,000	27,179,000
Investment income									1,705,000	1,558,000	1,268,000
Interest and debt expense									3,112,000	3,623,000	4,030,000
Depreciation and amortization									25,814,000	24,804,000	23,528,000
Operating income	50,950,000	49,533,000	48,670,000	34,092,000	35,808,000	35,886,000	39,982,000	28,295,000	183,245,000	139,971,000	113,742,000
Expenditures on long-lived assets									4,337,000	27,505,000	2,715,000
Goodwill	57,470,000				57,470,000				57,470,000	57,470,000	57,470,000
Capital lease additions									34,044,000	14,986,000	12,284,000
Total assets	808,449,000				683,882,000				808,449,000	683,882,000	648,792,000
Number of customers accounting for 10 percent or more of total revenue									0	0	0
Transportation Logistics [Member]
Segment Reporting Information [Line Items]
External revenue									2,614,739,000	2,366,032,000	1,972,863,000
Interest and debt expense									3,112,000	3,623,000	4,030,000
Depreciation and amortization									25,814,000	24,804,000	23,528,000
Operating income									156,354,000	116,512,000	88,176,000
Expenditures on long-lived assets									4,337,000	27,505,000	2,715,000
Goodwill	57,470,000				57,470,000				57,470,000	57,470,000	57,470,000
Capital lease additions									34,044,000	14,986,000	12,284,000
Total assets	647,002,000				576,334,000				647,002,000	576,334,000	524,584,000
Insurance [Member]
Segment Reporting Information [Line Items]
External revenue									34,343,000	34,138,000	35,933,000
Internal revenue									27,544,000	27,535,000	27,179,000
Investment income									1,705,000	1,558,000	1,268,000
Operating income									26,891,000	23,459,000	25,566,000
Total assets	$ 161,447,000				$ 107,548,000				$ 161,447,000	$ 107,548,000	$ 124,208,000