Note 1 - Summary of Significant Accounting Policies - Estimated Useful Lives (Details)	12 Months Ended
	Dec. 31, 2017
Tractor [Member]
Property, Plant and Equipment, Useful Life	5 years
Trailer [Member]
Property, Plant and Equipment, Useful Life	7 years
Service And Other Equipment [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life	3 years
Service And Other Equipment [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life	15 years
Building and Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life	20 years
Building and Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life	40 years