Note 14 - Provision for Income Taxes (Details) - USD ($)
$ in Thousands
12 Months Ended 36 Months Ended 48 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2013
Note 14 - Provision for Income Taxes (Details) [Line Items]          
Income Tax Expense (Benefit) $ 5,448 $ 14,145 $ 23,317    
Unrecognized Tax Benefits 4,588 2,981 1,718 $ 0 $ 1,718
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued $ 61 $ 46      
Biodiesel Blenders Credit [Member]          
Note 14 - Provision for Income Taxes (Details) [Line Items]          
Income Tax Expense (Benefit)     $ (3,878) $ (7,755) $ (11,633)
Domestic Tax Authority [Member] | Earliest Tax Year [Member]          
Note 14 - Provision for Income Taxes (Details) [Line Items]          
Open Tax Year 2012        
State and Local Jurisdiction [Member] | Earliest Tax Year [Member]          
Note 14 - Provision for Income Taxes (Details) [Line Items]          
Open Tax Year 2012