Quarterly report pursuant to Section 13 or 15(d)

Derivative Instrument and Hedging Transactions (Realized gain (loss)) (Details)

v3.5.0.2
Derivative Instrument and Hedging Transactions (Realized gain (loss)) (Details) - USD ($)
$ in Thousands
3 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Derivative [Line Items]    
(Gains) losses on derivative instruments: $ (3,891) $ (14,408)
Futures Commodity And Forwards Contracts And Open Purchase And Sale Commitments    
Derivative [Line Items]    
Unrealized gain on open future commodity and forward contracts and open sale and purchase commitments, net (18,150) (3,816)
Commodity Contract    
Derivative [Line Items]    
Realized losses (gains) on future commodity contracts, net $ 14,259 $ (10,592)