Goodwill and Long-Lived Asset Assessment (Details) (USD $)	3 Months Ended		12 Months Ended
	Apr. 30, 2010	Apr. 30, 2009	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2009
Goodwill [Line Items]
Goodwill			$ 0	$ 0
Goodwill, Impaired [Abstract]
Goodwill impairment test, market capitalization		721,800,000
Goodwill impairment test, carrying value including goodwill		949,000,000
Goodwill impairment test, assumed control rate (in percent)		25.00%
Goodwill impairment test, step one test valuation		902,200,000
Goodwill impairment test, implied fair value		0
Goodwill impairment		455,700,000	0	0	455,673,000
Tangible Asset Impairment Charges [Abstract]
Impairment of Long-Lived Assets Held-for-use	$ 0	$ 0