(Customer Relationships Acquired from Business Acquisitions) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Intangible assets
Net Carrying Value	$ 67,131
Customer relationships [Member]
Intangible assets
Gross Carrying Amount	77,706	38,706
Accumulated Amortization	(10,575)	(7,343)
Net Carrying Value	67,131	31,363
Customer relationships [Member] | TL [Member]
Intangible assets
Gross Carrying Amount	44,826	17,826
Accumulated Amortization	(6,902)	(5,294)
Net Carrying Value	37,924	12,532
Customer relationships [Member] | LTL [Member]
Intangible assets
Gross Carrying Amount	1,358	1,358
Accumulated Amortization	(893)	(723)
Net Carrying Value	465	635
Customer relationships [Member] | TMS [Member]
Intangible assets
Gross Carrying Amount	31,522	19,522
Accumulated Amortization	(2,780)	(1,326)
Net Carrying Value	$ 28,742	$ 18,196