Note 3 - Segment Information (Details) - Segment Summary (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Total Revenues:
Revenues	$ 170,843	$ 168,427	$ 508,061	$ 496,759
Operating Income (Loss):
Operating Income (Loss)	5,882	4,645	11,517	18,060
Operating Segments [Member] | Truckload [Member]
Total Revenues:
Revenues	160,107	161,625	479,511	477,800
Operating Income (Loss):
Operating Income (Loss)	6,831	7,612	17,969	25,176
Operating Segments [Member] | Other Segments [Member]
Total Revenues:
Revenues	10,736	6,802	28,550	18,959
Operating Income (Loss):
Operating Income (Loss)	366	(222)	575	(373)
Corporate, Non-Segment [Member]
Operating Income (Loss):
Operating Income (Loss)	$ (1,315)	$ (2,745)	$ (7,027)	$ (6,743)