Intangible Assets and Goodwill - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Oct. 31, 2014	Oct. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Identifiable intangible asset amortization expense recognized	$ 2.0	$ 2.0
Finite-lived intangible assets, amortization expense, year two	8.0
Finite-lived intangible assets, amortization expense, year three	8.0
Finite-lived intangible assets, amortization expense, year four	8.0
Finite-lived intangible assets, amortization expense, year five	8.0
Identifiable intangible asset amortization expense, after year five	8.0
Identifiable intangible asset amortization expense, remainder of fiscal year	$ 6.0