Discontinued Operations Operating Results, Details (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Apr. 30, 2013	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment charges		$ (100,412)	$ 190,505
Loss on write-down of assets held for sale	$ 15,658	$ 0	$ 15,658	$ 0