|
Fair Value Measurements (Details) (Commodity Contract [Member], Not Designated as Hedging Instrument [Member], USD $)
In Thousands, unless otherwise specified |
Jul. 31, 2014
|
Apr. 30, 2014
|
|---|---|---|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Commodity derivative asset | $ 0 | $ 114 |
| Commodity derivative liability | (12,661) | (7,321) |
|
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
|
||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Commodity derivative asset | 0 | 114 |
| Commodity derivative liability | (12,661) | (7,321) |
| Total | $ (12,661) | $ (7,207) |