Note 5 - Derivative Instruments (Tables)
12 Months Ended
Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Schedule of Derivative Instruments [Table Text Block]
   

Asset/(Liability)

 
   

2015

   

2014

 
   

Quantity

(contracts)

Long/

(Short)

   

Fair

Value

   

Quantity

(contracts)

Long/

(Short)

   

Fair

Value

 

Regulated options, included in other current assets

    (200

)

  $ (427

)

    (350

)

  $ (794

)

Regulated fixed price future commitments, included in other current assets

    (631

)

  $ 3,789       (225

)

  $ 862