Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plans Employee Benefit Plans - Additional Information (Details)

v3.8.0.1
Employee Benefit Plans Employee Benefit Plans - Additional Information (Details) - USD ($)
$ in Thousands
 12 Months Ended
Aug. 31, 2017
Aug. 31, 2016
Aug. 31, 2015
Defined Benefit Plan Disclosure [Line Items]      
Deferred Compensation Arrangement with Individual, Compensation Expense $ 1,600 $ 1,600 $ 1,800
Equity Securities      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Target Plan Asset Allocations Range Minimum 60.00%    
Defined Benefit Plan, Target Plan Asset Allocations Range Maximum 80.00%    
Other Postretirement Benefit Plan, Defined Benefit      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Benefit Obligation $ 3,800 4,000  
Foreign Defined Benefit Plan, Net Periodic Benefit Cost   0 (100)
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year $ 300    
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate 7.30%    
Defined Benefit Plan Health Care Cost Trend Rate In Future Period 5.00%    
United States Pension Plan of US Entity      
Defined Benefit Plan Disclosure [Line Items]      
Amount of benefits expected to be paid in fiscal 2018 $ 2,900    
Amount of benefits expected to be paid in fiscal 2019 2,900    
Amount of benefits expected to be paid in fiscal 2020 2,900    
Amount of benefits expected to be paid in, fiscal 2021 2,900    
Amount of benefits expected to be paid in, fiscal 2022 2,900    
Amount of benefits expected to be paid fiscal 2023 through fiscal 2027 14,600    
Defined Benefit Plan, Benefit Obligation 46,806 50,409 45,612
Foreign Defined Benefit Plan, Net Periodic Benefit Cost $ (36) $ (190) $ (395)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate 3.60% 3.45% 4.45%
Defined Benefit Plan, Accumulated Other Comprehensive Income Net Gains (Losses), after Tax $ (16,000) $ (18,400)  
Defined Benefit Plan, Amount to be Amortized from Accumulated Other Comprehensive Income (Loss) Next Fiscal Year $ 700    
Defined Benefit Plan, Expected Long Term Rate Of Returns On Assets Assumption 7.00%    
Other Current Liabilities and Other Long-term Liabilities [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Deferred Compensation Liability, Current and Noncurrent $ 20,900 22,200  
Non-US Pension Plans, Defined Benefit      
Defined Benefit Plan Disclosure [Line Items]      
Amount of benefits expected to be paid in fiscal 2018 300    
Amount of benefits expected to be paid in fiscal 2019 300    
Amount of benefits expected to be paid in fiscal 2020 400    
Amount of benefits expected to be paid in, fiscal 2021 500    
Amount of benefits expected to be paid in, fiscal 2022 600    
Amount of benefits expected to be paid fiscal 2023 through fiscal 2027 2,600    
Defined Benefit Plan, Benefit Obligation 14,645 16,808  
Foreign Defined Benefit Plan, Net Periodic Benefit Cost $ 1,000 $ 700 $ 1,000
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate 2.30% 1.90%  
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year $ 400    
Defined Benefit Plan, Expected Long Term Rate Of Returns On Assets Assumption 4.60%    
401(k) [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Contribution Plan, Employer Matching Contribution, Percent of Match 25.00%    
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay 6.00%    
Defined Contribution Plan, Cost Recognized $ 4,700 $ 4,400 4,300
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent 50.00%    
Maximum Percentage Of Core Contributions Made By Employer 3.00%    
Supplemental Executive Retirement Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Benefit Plan, Benefit Obligation $ 1,600    
Defined Contribution Plan, Cost Recognized $ 300 $ 300 $ 300
Minimum | Supplemental Executive Retirement Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Contribution Plan Employer Contribution Percentage 3.00%    
Maximum | Supplemental Executive Retirement Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Contribution Plan Employer Contribution Percentage 6.00%