Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013 Segment	Mar. 31, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Number of Operating Segments	3
Schedule of financial data of reportable segments
Revenues	$ 299,380	$ 236,574
Operating Income	19,137	14,640
Interest expense	1,875	1,847
Income before provision for income taxes	17,262	12,793
Depreciation and amortization	3,355	1,960
Capital expenditures	9,389	3,259
Total assets	723,690		700,808
LTL [Member]
Schedule of financial data of reportable segments
Revenues	132,691	118,953
Operating Income	8,978	8,450
Depreciation and amortization	778	515
Capital expenditures	1,450	2,587
Total assets	500,481		490,067
TL [Member]
Schedule of financial data of reportable segments
Revenues	146,541	98,027
Operating Income	9,668	5,662
Depreciation and amortization	2,397	1,259
Capital expenditures	7,915	644
Total assets	352,214		339,890
TMS [Member]
Schedule of financial data of reportable segments
Revenues	21,443	20,680
Operating Income	2,323	2,212
Depreciation and amortization	163	186
Capital expenditures	24	28
Total assets	65,595		61,076
Eliminations [Member]
Schedule of financial data of reportable segments
Revenues	(1,295)	(1,086)
Total assets	(194,600)		(190,225)
Corporate [Member]
Schedule of financial data of reportable segments
Operating Income	(1,832)	(1,684)
Depreciation and amortization	$ 17	$ 0