Note 5 - Property and Equipment - Property and Equipment, at Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property, plant, and equipment, gross	$ 518,406	$ 541,276
Revenue Equipment [Member]
Property, plant, and equipment, gross	400,282	435,865
Office Equipment [Member]
Property, plant, and equipment, gross	4,257	5,492
Land and Land Improvements [Member]
Property, plant, and equipment, gross	16,341	16,602
Building and Building Improvements [Member]
Property, plant, and equipment, gross	72,180	57,308
Construction in Progress [Member]
Property, plant, and equipment, gross	866	695
Property, Plant and Equipment, Other Types [Member]
Property, plant, and equipment, gross	$ 24,480	$ 25,314
Minimum [Member] | Revenue Equipment [Member]
Estimated useful lives (Year)	3 years
Minimum [Member] | Office Equipment [Member]
Estimated useful lives (Year)	5 years
Minimum [Member] | Land and Land Improvements [Member]
Estimated useful lives (Year)	0 years
Minimum [Member] | Building and Building Improvements [Member]
Estimated useful lives (Year)	7 years
Minimum [Member] | Property, Plant and Equipment, Other Types [Member]
Estimated useful lives (Year)	2 years
Maximum [Member] | Revenue Equipment [Member]
Estimated useful lives (Year)	10 years
Maximum [Member] | Office Equipment [Member]
Estimated useful lives (Year)	10 years
Maximum [Member] | Land and Land Improvements [Member]
Estimated useful lives (Year)	15 years
Maximum [Member] | Building and Building Improvements [Member]
Estimated useful lives (Year)	40 years
Maximum [Member] | Property, Plant and Equipment, Other Types [Member]
Estimated useful lives (Year)	10 years