Note 2 - Prepaid Expenses and Other (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Insurance premiums	$ 1,658	$ 1,730
Other	2,906	2,408
	19,307	18,134
Tires In Service [Member]
Prepaid expenses	5,351	5,064
License Fees Member [Member]
Prepaid expenses	5,042	4,921
Parts And Tires Inventory [Member]
Prepaid expenses	$ 4,350	$ 4,011