Note 4 - Related Party Transactions (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Purchase Of Fuel Tires And Related Services [Member]
Related Party Transaction, Amounts of Transaction	$ 335,000	$ 562,000	$ 585,000
Tire Purchases [Member]
Related Party Transaction, Amounts of Transaction	1,500,000	1,400,000	$ 1,600,000
Accounts Payable, Related Parties	$ 0	$ 19,000