Derivatives (Details) (USD $)	1 Months Ended	12 Months Ended					12 Months Ended		12 Months Ended		12 Months Ended
	Feb. 29, 2012 item	Jul. 31, 2013 Foreign currency forward contracts Fair value hedge instruments item	Jul. 31, 2012 Foreign currency forward contracts Fair value hedge instruments	Jul. 31, 2011 Foreign currency forward contracts Fair value hedge instruments	Jul. 31, 2013 Interest rate swap agreements Term Loan Facility	Aug. 08, 2012 Interest rate swap agreements Term Loan Facility	Jul. 31, 2013 Interest rate swap agreements Revolving Credit Facility	Aug. 08, 2012 Interest rate swap agreements Revolving Credit Facility	Jul. 31, 2013 Interest rate swap agreements Cash flow hedge instruments Term Loan Facility	Aug. 08, 2012 Interest rate swap agreements Cash flow hedge instruments Term Loan Facility	Jul. 31, 2013 Interest rate swap agreements Cash flow hedge instruments Revolving Credit Facility	Aug. 08, 2012 Interest rate swap agreements Cash flow hedge instruments Revolving Credit Facility
Derivatives
Term of contracts		1 month
Number of contracts		3
Aggregate value of contracts		$ 2,552,000
Term of renewed contracts		1 month
Net currency conversion loss, net of tax		86,000	20,000	146,000
Number of existing senior lenders of debt, whose variable interest cash flows will be exchanged by the entity with fixed interest cash flows	1
Borrowing initially hedged						40,000,000		25,000,000		40,000,000		25,000,000
Reference rate, description									one month LIBOR		one month LIBOR
Quarterly reduction in borrowings hedged					2,500,000				2,500,000
Semi-annual reduction in borrowings hedged							$ 5,000,000				$ 5,000,000
Reference rate (as a percent)									0.664%		0.496%