Financing Arrangements (Details) (USD $)	1 Months Ended			12 Months Ended								12 Months Ended					12 Months Ended			0 Months Ended	2 Months Ended		12 Months Ended		12 Months Ended			0 Months Ended	2 Months Ended	12 Months Ended			12 Months Ended
	Feb. 29, 2012 item	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013 Minimum	Jul. 31, 2013 Maximum	Jul. 31, 2013 Lender's base rate	Jul. 31, 2013 LIBOR Minimum	Jul. 31, 2013 LIBOR Maximum	Jul. 31, 2013 U.S. Credit Agreement	Sep. 30, 2013 U.S. Credit Agreement	Aug. 02, 2011 U.S. Credit Agreement	Jul. 31, 2013 U.S. Credit Agreement Minimum	Jul. 31, 2013 U.S. Credit Agreement Maximum	Jul. 31, 2013 U.S. Credit Agreement Lender's base rate	Jul. 31, 2013 U.S. Credit Agreement Lender's base rate Minimum	Jul. 31, 2013 U.S. Credit Agreement Lender's base rate Maximum	Jul. 31, 2013 U.S. Credit Agreement LIBOR	Jul. 31, 2013 U.S. Credit Agreement LIBOR Minimum	Jul. 31, 2013 U.S. Credit Agreement LIBOR Maximum	Aug. 02, 2011 Revolving Credit Facility	Sep. 30, 2013 Revolving Credit Facility	Jul. 31, 2013 Revolving Credit Facility	Jul. 31, 2013 Revolving Credit Facility Interest rate swap with fixed interest cash flows	Aug. 08, 2012 Revolving Credit Facility Interest rate swap with fixed interest cash flows	Jul. 31, 2013 Revolving Credit Facility One month LIBOR Interest rate swap with fixed interest cash flows	Aug. 02, 2011 Letters of credit	Aug. 02, 2011 Swing line loans	Aug. 02, 2011 Term Loan Facility	Sep. 30, 2013 Term Loan Facility	Jul. 31, 2013 Term Loan Facility item	Jul. 31, 2013 Term Loan Facility Interest rate swap with fixed interest cash flows	Aug. 08, 2012 Term Loan Facility Interest rate swap with fixed interest cash flows	Jul. 31, 2013 Term Loan Facility One month LIBOR Interest rate swap with fixed interest cash flows
Financing Arrangements
Maximum borrowing capacity											$ 150,000,000									$ 100,000,000						$ 20,000,000	$ 5,000,000
Borrowings																												50,000,000
Term of line of credit facility																				5 years
Maximum additional borrowing capacity available at the entity's option																				50,000,000
Unamortized debt issuance costs		764,000	1,074,000
Margin on reference rate (as a percent)														0.75%	0.25%	2.00%	1.75%	1.25%	3.00%
Reference rate, description				One month LIBOR	Twelve month LIBOR									lender's base rate			LIBOR								one month LIBOR								one month LIBOR
Reference rate (as a percent)						3.25%	0.19%	0.87%																	0.496%								0.664%
Fees on unused portion of credit facilities (as a percent)									0.30%			0.25%	0.50%
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																								25,000,000								40,000,000
Quarterly reduction in borrowings hedged																															2,500,000
Semi-annual reduction in borrowings hedged																							5,000,000
Number of quarterly principal installments																														20
Quarterly principal installments																														2,500,000
Mandatory prepayments of amounts outstanding as a percentage of net proceeds received from certain sales or other dispositions of all or any part of the entity and its subsidiaries' assets									100.00%
Mandatory prepayments of amounts outstanding as a percentage of certain insurance and condemnation proceeds received by the entity or any of its subsidiaries									100.00%
Mandatory prepayments of amounts outstanding as a percentage of net cash proceeds received from issuance or occurrence of any indebtedness of the entity or any of its subsidiaries									100.00%
Mandatory prepayments of amounts outstanding as a percentage of net proceeds from sale of certain equity									100.00%
Shares of foreign subsidiaries pledged as security (as a percent)									65.00%
Outstanding borrowings									95,000,000	84,500,000												65,000,000								30,000,000
Available borrowing capacity																						35,000,000
Repayment of borrowings																					$ 8,000,000								$ 2,500,000