Note 3 - Reinstatement of BTC and Small Agri-biodiesel Producers Tax Credit (Details)
$ in Thousands, gal in Millions
3 Months Ended 12 Months Ended 15 Months Ended
Jan. 03, 2013
$ / gal
gal
Dec. 31, 2014
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Dec. 31, 2012
USD ($)
Dec. 31, 2015
USD ($)
Biodiesel Blenders Credit [Member]            
Note 3 - Reinstatement of BTC and Small Agri-biodiesel Producers Tax Credit (Details) [Line Items]            
Income Tax Credits and Adjustments   $ 28,954 $ 30,895   $ 2,535 $ 33,031
Biodiesel Blenders Credit [Member] | Owed to Customers [Member]            
Note 3 - Reinstatement of BTC and Small Agri-biodiesel Producers Tax Credit (Details) [Line Items]            
Income Tax Credits and Adjustments     16,544 $ 18,628    
Small Agri-biodiesel Producers Credit [Member]            
Note 3 - Reinstatement of BTC and Small Agri-biodiesel Producers Tax Credit (Details) [Line Items]            
Income Tax Credits and Adjustments         $ 1,500  
Maximum Production Capacity, Number of Gallons (in US Gallons) | gal 60          
Tax Credit Per Gallon of Agri-Biodiesel Sold (in Dollars per US Gallon) | $ / gal 0.10          
Number of Gallons Sold (in US Gallons) | gal 15          
Small Agri-biodiesel Producers Credit [Member] | The Total Amount for 2015 and 2014 Adjustments [Member]            
Note 3 - Reinstatement of BTC and Small Agri-biodiesel Producers Tax Credit (Details) [Line Items]            
Income Tax Credits and Adjustments     $ 1,500