Note 8 - Summary of Rental Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue Equipment [Member]
Lease and rental expense	$ 12,611	$ 20,935	$ 22,991
Land and Building [Member]
Lease and rental expense	2,078	3,561	4,044
Other Machinery and Equipment [Member]
Lease and rental expense	340	317	362
Lease and rental expense	$ 15,029	$ 24,813	$ 27,397