Note 3 - Segment Information (Details) - Segment Information (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Segment Reporting Information [Line Items]
Revenues	$ 172,488	$ 171,301	$ 337,219	$ 328,332
Operating Income (Loss)	6,350	11,059	5,635	13,416
Asset-Based Truckload Services [Member]
Segment Reporting Information [Line Items]
Revenues	161,883	163,798	319,405	316,175
Operating Income (Loss)	7,967	11,333	11,138	17,527
Other Segments [Member]
Segment Reporting Information [Line Items]
Revenues	10,604	7,503	17,814	12,157
Operating Income (Loss)	475	(152)	208	(151)
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)	$ (2,092)	$ (122)	$ (5,711)	$ (3,960)