Goodwill And Intangible Assets (Schedule Of Changes In Gross Carrying Amounts Of Goodwill) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Sep. 30, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Goodwill [Line Items]
Goodwill		$ 521,213	$ 520,765	$ 520,699
Accumulated impairment losses		(183,049)	(183,049)	(183,049)
Total Goodwill		338,164	337,716	337,650
Impairment charge	(16,400)
Change in foreign currency exchange rates		448	66
Logistics [Member]
Goodwill [Line Items]
Goodwill		55,888	55,440	55,374
Accumulated impairment losses		(48,236)	(48,236)	(48,236)
Total Goodwill		7,652	7,204	7,138
Change in foreign currency exchange rates		448	66
Truckload [Member]
Goodwill [Line Items]
Goodwill		464,598	464,598	464,598
Accumulated impairment losses		(134,813)	(134,813)	(134,813)
Total Goodwill		329,785	329,785	329,785
Change in foreign currency exchange rates		0	0
Other [Member]
Goodwill [Line Items]
Goodwill		727	727	727
Accumulated impairment losses		0	0	0
Total Goodwill		727	727	727
Change in foreign currency exchange rates		$ 0	$ 0