Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended
	Dec. 31, 2013	Oct. 31, 2014	Oct. 31, 2013	Jul. 31, 2014
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill		$ 57,589,000		$ 56,955,000
Acquisition of goodwill		600,000
Non-Amortizable Trade names, cost		7,600,000		7,600,000
Amortization expense related to acquired intangible assets		2,200,000	1,900,000
Impairment for goodwill and other intangible assets with indefinite lives	$ 0
Minimum
Goodwill and Intangible Assets Disclosure [Line Items]
Intangible assets, estimated useful lives		1 year
Maximum
Goodwill and Intangible Assets Disclosure [Line Items]
Intangible assets, estimated useful lives		14 years