Derivatives (Details) (USD $)	1 Months Ended	3 Months Ended				3 Months Ended		3 Months Ended		3 Months Ended
	Feb. 29, 2012 item	Oct. 31, 2013 Foreign currency forward contracts Fair value hedge instruments item	Oct. 31, 2012 Foreign currency forward contracts Fair value hedge instruments	Oct. 31, 2013 Interest rate swap agreements Term Loan Facility	Aug. 08, 2012 Interest rate swap agreements Term Loan Facility	Oct. 31, 2013 Interest rate swap agreements Revolving Credit Facility	Aug. 08, 2012 Interest rate swap agreements Revolving Credit Facility	Oct. 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	Oct. 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		2
Aggregate value of contracts		$ 6,381,000
Term of renewed contracts		1 month
Net currency conversion loss, net of tax		62,000	15,000
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%