Long-Term Debt Long-Term Debt (Narrative) (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|
Jan. 31, 2016 |
Jan. 31, 2015 |
Jan. 31, 2016 |
Jan. 31, 2015 |
Jul. 31, 2015 |
|
| Gross interest expense | $ 10,900 | $ 13,800 | $ 21,500 | $ 27,400 | |
| Long-term Debt | 695,535 | 635,935 | 695,535 | 635,935 | $ 816,830 |
| Amortization of deferred financing costs | 200 | 400 | 500 | 700 | |
| Interest costs incurred, capitalized | 0 | 0 | 0 | 0 | |
| Industrial Development Bonds [Member] | |||||
| Long-term Debt | $ 0 | $ 215,000 | $ 0 | $ 215,000 | $ 0 |