Quarterly report pursuant to Section 13 or 15(d)

Derivative Instruments and Hedging Transactions (Outstanding Commitments) (Details)

v3.10.0.1
Derivative Instruments and Hedging Transactions (Outstanding Commitments) (Details) - USD ($)
$ in Thousands
Sep. 30, 2018
Jun. 30, 2018
Derivative [Line Items]    
Purchase commitments $ 264,037 $ 342,287
Sales commitments (215,464) (138,022)
Margin sales commitments (5,674) (5,988)
Open derivative contracts 288,247 347,415
Forward contracts    
Derivative [Line Items]    
Open derivative contracts 197,419 274,994
Future contracts    
Derivative [Line Items]    
Open derivative contracts $ 90,828 $ 72,421