Income Taxes - Additional Information (Detail) (USD $)	0 Months Ended	9 Months Ended	0 Months Ended
	Oct. 09, 2014	Apr. 30, 2015	Dec. 29, 2014	Jul. 31, 2014
Income Taxes [Line Items]
Unrecognized tax benefits related to federal, state and foreign taxes		$ 1,500,000		$ 1,000,000
Income tax positions penalties accrued		0
Expected any unrecognized tax benefits to reverse in the next twelve months		$ 0
Stockholder owning ownership on corporation's securities percentage		5.00%
Stockholder owning ownership on corporation's securities rolling period		3 years
Amended expiration date of the Tax Plan	Oct. 17, 2017
Maximum
Income Taxes [Line Items]
Percentage of common shares outstanding permitted for acquired by HNH and its affiliates			45.00%
Protective Amendment | Minimum
Income Taxes [Line Items]
Percentage of ownership require to obtain approval from board of directors to acquiring shares of the company's securities			4.99%
Tax Benefit Preservation Plan
Income Taxes [Line Items]
Tax Benefit Preservation Plan, adoption date		2011-10-17
Tax Benefit Preservation Plan | Minimum
Income Taxes [Line Items]
Percentage of ownership require to obtain approval from board of directors to acquiring shares of the company's securities		4.99%
United States | Federal
Income Taxes [Line Items]
Tax examinations tax period		Tax years ended July 31, 2010 through July 31, 2014
Europe | Foreign
Income Taxes [Line Items]
Tax examinations tax period		2006 through 2013 tax years
Asia | Foreign
Income Taxes [Line Items]
Tax examinations tax period		2002 through 2013 tax years