Note 16 - Segment Information (Details Textual) $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 31, 2018 USD ($)	[1]	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	[1]	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Number of Reportable Segments											2
Revenues, Total	$ 272,268		$ 243,303	$ 196,318	$ 173,566	$ 203,306		$ 178,631	$ 164,326	$ 158,744
Managed Freight [Member] | Tractors and Warehouse Space [Member]
Operating Leases, Income Statement, Lease Revenue, Total											$ 900
Managed Freight [Member] | Factoring [Member]
Revenues, Total											5,000	$ 3,100	$ 2,600
Managed Freight [Member] | Warehouse [Member] | Landair [Member]
Revenues, Total											23,600
Truckload [Member] | Tractors and Warehouse Space [Member]
Operating Leases, Income Statement, Lease Revenue, Total											$ 3,900

[1] Includes $40.1 million one-time benefit related to the Tax Act.