| Derivative Instrument and Hedging Transactions (Outstanding Commitments) (Details) - USD ($) $ in Thousands | Jun. 30, 2016 | Jun. 30, 2015 | 
|---|---|---|
| Derivative [Line Items] | ||
| Purchase commitments | $ 550,810 | $ 444,023 | 
| Sales commitments | (237,325) | (249,081) | 
| Margin sales commitments | (12,439) | (12,430) | 
| Open derivative contracts | 474,979 | 310,316 | 
| Forward contracts | ||
| Derivative [Line Items] | ||
| Open derivative contracts | 188,530 | 202,323 | 
| Future contracts | ||
| Derivative [Line Items] | ||
| Open derivative contracts | $ 286,449 | $ 107,993 | 
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- Definition Margin Sale Commitments No definition available. 
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- Definition Open Inventory Purchase Commitments No definition available. 
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- Definition Open Inventory Sale Commitments No definition available. 
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- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
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