Annual report pursuant to Section 13 and 15(d)

Changes in Projected Benefit Obligations, Fair Value of Plan Assets and Funded Status of Defined Benefit Pension Plans (Detail)

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Changes in Projected Benefit Obligations, Fair Value of Plan Assets and Funded Status of Defined Benefit Pension Plans (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Aug. 31, 2018
Aug. 31, 2017
Aug. 31, 2016
Reconciliation of plan assets:      
Fair value of plan assets at beginning of year $ 40,027    
Fair value of plan assets at end of year 40,244 $ 40,027  
Fair Value, Inputs, Level 2 | Fixed Income Securities      
Reconciliation of plan assets:      
Fair value of plan assets at beginning of year 11,614    
Fair value of plan assets at end of year 19,921 11,614  
Domestic Plan [Member]      
Reconciliation of benefit obligations:      
Benefit obligation at beginning of year 46,806 50,409  
Interest cost 1,633 1,690 $ 1,970
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) (2,330) (1,997)  
Defined Benefit Plan, Benefit Obligation, Benefits Paid (2,829) (3,296)  
Benefit obligation at end of year 43,280 46,806 50,409
Reconciliation of plan assets:      
Fair value of plan assets at beginning of year 40,027 39,489  
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) 2,938 3,599  
Defined Benefit Plan, Plan Assets, Contributions by Employer 108 235  
Defined Benefit Plan, Plan Assets, Benefits Paid (2,829) (3,296)  
Fair value of plan assets at end of year 40,244 40,027 $ 39,489
Funded status of the plans (underfunded) $ (3,036) $ (6,779)