Acquisitions (Details Textual) (USD $)	3 Months Ended			3 Months Ended		3 Months Ended		3 Months Ended		3 Months Ended		3 Months Ended		3 Months Ended
	Mar. 31, 2012	Mar. 31, 2013 CTL [Member]	Feb. 24, 2012 CTL [Member]	Mar. 31, 2013 D&E [Member]	Apr. 19, 2012 D&E [Member]	Mar. 31, 2013 CTW [Member]	Jun. 04, 2012 CTW [Member]	Mar. 31, 2013 R and M [Member]	Aug. 01, 2012 R and M [Member]	Mar. 31, 2013 EFS [Member]	Aug. 10, 2012 EFS [Member]	Mar. 31, 2013 Central Cal [Member]	Nov. 05, 2012 Central Cal [Member]	Mar. 31, 2013 Brandon Carrier Group Inc [Member]	Mar. 31, 2013 Direct Connection Transport (DCT) [Member]	Feb. 24, 2012 2012 [Member] CTL [Member]	Mar. 31, 2013 2012 [Member] D&E [Member]	Mar. 31, 2013 2012 [Member] CTW [Member]	Mar. 31, 2013 2013 [Member] CTL [Member]	Mar. 31, 2013 2013 [Member] D&E [Member]	Mar. 31, 2013 2013 [Member] CTW [Member]	Mar. 31, 2013 2013 [Member] R and M [Member]	Mar. 31, 2013 2013 [Member] EFS [Member]	Mar. 31, 2013 2013 [Member] Central Cal [Member]	Mar. 31, 2013 2013 [Member] Brandon Carrier Group Inc [Member]	Mar. 31, 2013 2013 [Member] Direct Connection Transport (DCT) [Member]	Mar. 31, 2013 2014 [Member] CTW [Member]	Mar. 31, 2013 2014 [Member] R and M [Member]	Mar. 31, 2013 2014 [Member] EFS [Member]	Mar. 31, 2013 2014 [Member] Central Cal [Member]	Mar. 31, 2013 2014 [Member] Brandon Carrier Group Inc [Member]	Mar. 31, 2013 2014 [Member] Direct Connection Transport (DCT) [Member]	Mar. 31, 2013 2015 [Member] R and M [Member]	Mar. 31, 2013 2015 [Member] EFS [Member]	Mar. 31, 2013 2015 [Member] Central Cal [Member]	Mar. 31, 2013 2015 [Member] Brandon Carrier Group Inc [Member]	Mar. 31, 2013 2015 [Member] Direct Connection Transport (DCT) [Member]	Mar. 31, 2013 2016 [Member] EFS [Member]	Mar. 31, 2013 2016 [Member] Central Cal [Member]	Mar. 31, 2013 2016 [Member] Brandon Carrier Group Inc [Member]	Feb. 24, 2012 TMS [Member] CTL [Member]	Apr. 19, 2012 TL [Member] D&E [Member]	Jun. 04, 2012 TL [Member] CTW [Member]	Aug. 01, 2012 TL [Member] R and M [Member]	Nov. 05, 2012 TL [Member] Central Cal [Member]	Nov. 12, 2012 TL [Member] Brandon Carrier Group Inc [Member]	Dec. 21, 2012 TL [Member] Direct Connection Transport (DCT) [Member]	Aug. 10, 2012 LTL [Member] EFS [Member]	Mar. 31, 2013 Maximum [Member] D&E [Member]	Mar. 31, 2013 Minimum [Member] D&E [Member]
Business Acquisition (Textual) [Abstract]
Date of acquisition		Feb. 24, 2012		Apr. 19, 2012		Jun. 04, 2012		Aug. 01, 2012		Aug. 10, 2012		Nov. 05, 2012		Nov. 12, 2012	Dec. 21, 2012
Total consideration paid to acquire			$ 6,200,000		$ 11,400,000		$ 7,600,000		$ 24,200,000		$ 10,000,000		$ 3,800,000																																	$ 24,100,000	$ 1,000,000
Contingent consideration, capped earn out		800,000				3,500,000		5,000,000		4,000,000		4,000,000		2,500,000	1,000,000																																		700,000	100,000
Receive a payment equal to the amount by which entity annual operating income, as defined in the purchase agreement				5,000,000				1,700,000		900,000		800,000				1,800,000	2,000,000	2,000,000	1,800,000	2,000,000	2,000,000	4,500,000	2,300,000	1,400,000	3,000,000	400,000	2,000,000	4,500,000	2,500,000	1,800,000	3,000,000	400,000	4,500,000	2,500,000	1,800,000	3,000,000	400,000	2,800,000	1,800,000	3,000,000
Contingent purchase price related to acquisitions																																									700,000	1,000,000	2,600,000	4,200,000	3,400,000	2,200,000	1,000,000	3,100,000
Revenue of acquiree since acquisition date, actual	700,000
Impact on revenue on a pro forma basis	286,687,000
Impact on net income on a pro forma basis	8,596,000
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual	$ 100,000