Revolving Credit Facilities and Mortgage Payable - Domestic Line of Credit (Details)	1 Months Ended	2 Months Ended	12 Months Ended
	Nov. 30, 2014 USD ($)	May 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	May 25, 2018 USD ($)	Aug. 31, 2015 USD ($)
Line of Credit | Revolving Credit Facility
Notes Payable and Long-Term Debt
Deferred financing costs			$ 600,000
Credit Agreement
Notes Payable and Long-Term Debt
Term of agreement (in years)	5 years
Current borrowing capacity	$ 400,000,000				$ 600,000,000
Capacity available for foreign currency borrowings					150,000,000
Credit Agreement | LIBOR based interest rates
Notes Payable and Long-Term Debt
Spread on variable interest rate (as a percent)			1.25%
Interest rate, effective percentage			3.13%
Credit Agreement | Alternate Base Rate based interest rates
Notes Payable and Long-Term Debt
Spread on variable interest rate (as a percent)			0.25%
Interest rate, effective percentage			5.00%
Second Amended And Restated Credit Agreement, As Amended
Notes Payable and Long-Term Debt
Borrowing capacity increase available					$ 200,000,000
Unused capacity commitment fee			0.175%
Second Amended And Restated Credit Agreement, As Amended | Federal Funds Effective Rate
Notes Payable and Long-Term Debt
Spread on variable interest rate (as a percent)			0.50%
Second Amended And Restated Credit Agreement, As Amended | Line of Credit | Revolving Credit Facility
Notes Payable and Long-Term Debt
Proceeds from lines of credit			$ 185,000,000
Repayments of lines of credit			185,000,000
Long-term line of credit			0
Amount available under the credit agreement			399,451,000
Outstanding letters of credit			$ 549,000
Second Amended And Restated Credit Agreement, As Amended | Line of Credit | Revolving Credit Facility | Subsequent Event
Notes Payable and Long-Term Debt
Proceeds from lines of credit		$ 0
Long-term line of credit				$ 0
Amount available under the credit agreement				$ 399,451,000
Minimum | Second Amended And Restated Credit Agreement, As Amended
Notes Payable and Long-Term Debt
Asset coverage ratio numerator			3.25
Ratio consolidated EBITDA plus annual rental expense to annual interest expense plus rental expense numerator			2.25
Maximum | Credit Agreement | LIBOR based interest rates
Notes Payable and Long-Term Debt
Spread on variable interest rate (as a percent)			2.00%
Maximum | Credit Agreement | Alternate Base Rate based interest rates
Notes Payable and Long-Term Debt
Spread on variable interest rate (as a percent)			1.25%
Maximum | Second Amended And Restated Credit Agreement, As Amended
Notes Payable and Long-Term Debt
Capacity available for letters of credit	75,000,000
Capacity available for swing loans	$ 5,000,000
Unused capacity commitment fee			0.30%
Capital expenditures allowed			$ 110,000,000
Additional unsecured debt allowed			$ 200,000,000
Total adjusted leverage ratio numerator			2.75
Maximum | Second Amended And Restated Credit Agreement, As Amended | Alternate Base Rate based interest rates
Notes Payable and Long-Term Debt
Spread on variable interest rate (as a percent)			1.00%
Other Current Assets | Line of Credit | Revolving Credit Facility
Notes Payable and Long-Term Debt
Deferred financing costs			$ 400,000
Other Assets | Line of Credit | Revolving Credit Facility
Notes Payable and Long-Term Debt
Deferred financing costs			$ 200,000