Segment Reporting (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) Segment	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Segment Reporting Information [Line Items]
Number of Operating Segments | Segment			3
Schedule of financial data of reportable segments
Revenues	$ 497,173	$ 498,086	$ 1,504,073	$ 1,340,298
Operating Income	14,359	25,280	72,403	71,472
Interest expense	4,913	3,827	13,895	8,936
Income before provision for income taxes	9,446	21,453	58,508	62,536
Depreciation and amortization	8,443	6,319	22,855	16,788
Capital expenditures, cash and non-cash	15,492	9,075	49,682	30,556
Total assets	1,329,358		1,329,358		$ 1,257,820
Global Solutions [Member]
Schedule of financial data of reportable segments
Revenues	82,392	87,240	254,127	225,695
Operating Income	6,612	6,708	20,123	16,273
Depreciation and amortization	1,024	866	3,021	2,333
Capital expenditures, cash and non-cash	2,530	261	2,978	1,278
Total assets	245,088		245,088		242,512
TL [Member]
Schedule of financial data of reportable segments
Revenues	292,951	262,865	870,614	687,539
Operating Income	15,277	18,474	51,720	46,500
Depreciation and amortization	6,236	4,266	16,414	11,050
Capital expenditures, cash and non-cash	10,198	6,311	31,817	22,570
Total assets	815,535		815,535		691,096
LTL [Member]
Schedule of financial data of reportable segments
Revenues	127,284	151,069	397,872	436,232
Operating Income	1,955	5,478	18,981	20,154
Depreciation and amortization	822	912	2,394	2,531
Capital expenditures, cash and non-cash	2,120	1,963	6,391	4,142
Total assets	738,157		738,157		782,268
Corporate, Non-Segment [Member]
Schedule of financial data of reportable segments
Operating Income	(9,485)	(5,380)	(18,421)	(11,455)
Depreciation and amortization	361	275	1,026	874
Capital expenditures, cash and non-cash	644	540	8,496	2,566
Total assets	11,996		11,996		4,919
Consolidation, Eliminations [Member]
Schedule of financial data of reportable segments
Revenues	(5,454)	$ (3,088)	(18,540)	$ (9,168)
Total assets	$ (481,418)		$ (481,418)		$ (462,975)