Goodwill And Intangible Assets (Schedule Of Changes In Gross Carrying Amounts Of Goodwill) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill [Line Items]
Goodwill	$ 520,628us-gaap_GoodwillGross	$ 521,020us-gaap_GoodwillGross	$ 521,213us-gaap_GoodwillGross
Accumulated impairment losses	(183,049)	(183,049)	(183,049)
Change in foreign currency exchange rates	(392)us-gaap_GoodwillTranslationAdjustments	(193)us-gaap_GoodwillTranslationAdjustments
Total Goodwill	337,579us-gaap_Goodwill	337,971us-gaap_Goodwill	338,164us-gaap_Goodwill
Logistics
Goodwill [Line Items]
Goodwill	55,303	55,695	55,888
Accumulated impairment losses	(48,236)	(48,236)	(48,236)
Change in foreign currency exchange rates	(392)	(193)
Total Goodwill	7,067	7,459	7,652
Truckload
Goodwill [Line Items]
Goodwill	464,598	464,598	464,598
Accumulated impairment losses	(134,813)	(134,813)	(134,813)
Change in foreign currency exchange rates	0	0
Total Goodwill	329,785	329,785	329,785
Corporate and Eliminations
Goodwill [Line Items]
Goodwill	727	727	727
Accumulated impairment losses	0	0	0
Change in foreign currency exchange rates	0	0
Total Goodwill	$ 727	$ 727	$ 727

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

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-Section 45

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Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

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+ References

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-Name Accounting Standards Codification

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