Note 5 - Segment Information - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Revenue	$ 274,016	$ 317,377	$ 540,867	$ 608,962
Operating income	11,783	26,873	29,415	50,720
Operating Segments [Member]
Revenue	274,016	317,377	540,867	608,962
Operating income	11,783	26,873	29,415	50,720
Intersegment Eliminations [Member]
Revenue	3,915	1,006	8,377	1,897
Consolidation, Eliminations [Member]
Revenue	(3,915)	(1,006)	(8,377)	(1,897)
Expedited [Member] | Operating Segments [Member]
Revenue	104,073	121,643	204,969	220,440
Operating income	5,815	14,610	15,091	23,941
Expedited [Member] | Intersegment Eliminations [Member]
Revenue	3,915	1,006	8,377	1,897
Dedicated [Member] | Operating Segments [Member]
Revenue	81,194	96,767	161,438	185,714
Operating income	3,243	2,882	10,390	5,523
Dedicated [Member] | Intersegment Eliminations [Member]
Revenue	0	0	0	0
Managed Freight [Member] | Operating Segments [Member]
Revenue	63,281	80,281	124,155	166,432
Operating income	1,945	8,627	3,163	19,458
Managed Freight [Member] | Intersegment Eliminations [Member]
Revenue	0	0	0	0
Warehousing [Member] | Operating Segments [Member]
Revenue	25,468	18,686	50,305	36,376
Operating income	780	754	771	1,798
Warehousing [Member] | Intersegment Eliminations [Member]
Revenue	$ 0	$ 0	$ 0	$ 0