Financing Arrangements (Details) (USD $)	1 Months Ended	9 Months Ended	0 Months Ended	1 Months Ended	9 Months Ended	0 Months Ended
	Feb. 29, 2012 Lender	Apr. 30, 2014	Mar. 04, 2014	May 31, 2015	Apr. 30, 2015	Aug. 08, 2012
Financing Arrangements
Unamortized debt issuance costs					$ 1,403,000
Number of existing senior lenders of debt, whose variable interest cash flows will be exchanged by the entity with fixed interest cash flows	1
Repayment of borrowings		5,000,000
Credit Agreement
Financing Arrangements
Maximum borrowing capacity			250,000,000
Debt issuance costs			1,318,000
Fees on unused portion of credit facilities (as a percent)					0.20%
Shares of foreign subsidiaries pledged as security (as a percent)					65.00%
Outstanding borrowings				87,500,000	91,500,000
Repayment of borrowings				4,000,000
Credit Agreement | Minimum
Financing Arrangements
Fees on unused portion of credit facilities (as a percent)					0.20%
Credit Agreement | Maximum
Financing Arrangements
Fees on unused portion of credit facilities (as a percent)					0.40%
Credit Agreement | Lender's base rate
Financing Arrangements
Margin on reference rate (as a percent)					0.25%
Reference rate (as a percent)					3.50%
Credit Agreement | Lender's base rate | Minimum
Financing Arrangements
Margin on reference rate (as a percent)					0.25%
Credit Agreement | Lender's base rate | Maximum
Financing Arrangements
Margin on reference rate (as a percent)					1.25%
Credit Agreement | LIBOR
Financing Arrangements
Margin on reference rate (as a percent)					1.25%
Credit Agreement | LIBOR | Minimum
Financing Arrangements
Margin on reference rate (as a percent)					1.25%
Reference rate (as a percent)					0.18%
Credit Agreement | LIBOR | Maximum
Financing Arrangements
Margin on reference rate (as a percent)					2.25%
Reference rate (as a percent)					0.70%
Revolving Credit Facility
Financing Arrangements
Maximum borrowing capacity		100,000,000	250,000,000
Term of line of credit facility			5 years
Maximum additional borrowing capacity available at the entity's option			100,000,000
Unamortized debt issuance costs			512,000
Revolving Credit Facility | Interest rate swap agreements | Designated as hedging instrument | Cash flow hedge instruments
Financing Arrangements
Borrowing initially hedged						25,000,000
Semi-annual reduction in borrowings hedged						5,000,000
Revolving Credit Facility | One month LIBOR | Interest rate swap agreements | Designated as hedging instrument | Cash flow hedge instruments
Financing Arrangements
Interest rate (as a percent)						0.496%
Term Loan Facility
Financing Arrangements
Borrowings		50,000,000
Unamortized debt issuance costs charged to interest expense			84,000
Term Loan Facility | Interest rate swap agreements | Designated as hedging instrument | Cash flow hedge instruments
Financing Arrangements
Borrowing initially hedged						40,000,000
Quarterly reduction in borrowings hedged						2,500,000
Term Loan Facility | One month LIBOR | Interest rate swap agreements | Designated as hedging instrument | Cash flow hedge instruments
Financing Arrangements
Interest rate (as a percent)						0.664%
Borrowings of foreign currency
Financing Arrangements
Maximum borrowing capacity			100,000,000
Letters of credit
Financing Arrangements
Maximum borrowing capacity			30,000,000
Swing line loans
Financing Arrangements
Maximum borrowing capacity			$ 10,000,000