Note 3 - Segment Information - Segment by Operating Fleet Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue	$ 222,914	$ 243,303	$ 661,393	$ 613,187
Truckload [Member]
Revenue	174,958	197,053	523,026	522,312
Truckload [Member] | Expedited [Member]
Revenue	68,306	84,202	197,557	250,553
Truckload [Member] | Dedicated [Member]
Revenue	82,692	74,493	243,436	164,966
Truckload [Member] | Refrigerated [Member]
Revenue	19,368	33,672	68,107	102,107
Truckload [Member] | Over the Road [Member]
Revenue	4,592	4,686	13,926	4,686
Managed Freight [Member]
Revenue	47,956	46,250	138,367	90,875
Managed Freight [Member] | Brokerage [Member]
Revenue	24,016	26,159	68,601	68,741
Managed Freight [Member] | Transportation Management Services [Member]
Revenue	9,323	6,991	27,124	6,991
Managed Freight [Member] | Shuttle and Switching [Member]
Revenue	3,693	3,451	10,990	3,451
Managed Freight [Member] | Warehouse [Member]
Revenue	8,469	8,258	25,091	8,258
Managed Freight [Member] | Factoring [Member]
Revenue	$ 2,455	$ 1,391	$ 6,561	$ 3,434