Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended	12 Months Ended			3 Months Ended			12 Months Ended
	Apr. 30, 2011	Apr. 30, 2010	Apr. 30, 2011	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010	Apr. 30, 2011 Non-Cash trademark	Apr. 30, 2010 Non-Cash trademark	Oct. 31, 2010 Trademarks	Jul. 31, 2012 Trademarks Year	Jul. 31, 2012 Heartland Year
Goodwill And Intangible Assets [Line Items]
Aggregate amortization expense for amortizable intangibles				$ 11,135	$ 10,262	$ 510
Definite-lived assets, useful life											25
Amortization period, Minimum years										20
Amortization period, Maximum years										25
Indefinite-lived intangible assets impairment							1,430	500	2,036
Goodwill, impairment loss	$ 0	$ 0	$ 0