Note 7 - Debt (Details) - Current and Long-term Debt (Parentheticals)	Mar. 31, 2015	Dec. 31, 2014
Revenue Equipment Installment Notes [Member]
Note 7 - Debt (Details) - Current and Long-term Debt (Parentheticals) [Line Items]
Interest rate on notes payable, current	3.70%	3.80%
Interest rate on notes payable, long-term	3.70%	3.80%
Real Estate Note [Member]
Note 7 - Debt (Details) - Current and Long-term Debt (Parentheticals) [Line Items]
Interest rate on notes payable, current	2.50%	2.50%
Interest rate on notes payable, long-term	2.50%	2.50%
Other Note Payable [Member]
Note 7 - Debt (Details) - Current and Long-term Debt (Parentheticals) [Line Items]
Interest rate on notes payable, current	3.00%	3.00%
Interest rate on notes payable, long-term	3.00%	3.00%