Postretirement and Other Employee Benefits (Benefit Obligations and Plan Assets, Changes in Benefit Obligation and Plan Assets and Funded Status of Plans) (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2016
Change in projected benefit obligation
Beginning projected benefit obligation	$ 167,714	$ 182,278
Service cost	1,063	1,068	$ 883
Interest cost	3,807	2,942	4,844
Actuarial (gain) loss	(6,019)	(10,147)
Curtailments gain	(998)	0
Settlements paid from plan assets	0	(2,133)
Total benefits paid	(6,211)	(6,790)
Plan participants’ contributions	31	27
Amendments	1,864	0
Terminations	0	(106)
Effect of conversion to U.S. dollars	(147)	575
Ending projected benefit obligation	161,104	167,714	182,278
Change in plan assets
Beginning fair value of plan assets	146,698	143,702
Actual return on plan assets	8,146	2,582
Settlements paid from plan assets	0	(2,133)
Employer contributions	1,811	6,981
Benefits paid from plan assets	(4,758)	(3,759)
Plan participants’ contributions	31	27
Effect of conversion to U.S. dollars	(213)	(702)
Ending fair value of plan assets	151,715	146,698	$ 143,702
Unfunded status	(9,389)	(21,016)
Amounts recognized in the Consolidated Balance Sheets
Accrued benefit liability, current	428	182
Accrued benefit liability, noncurrent	8,961	20,834
Accumulated other comprehensive loss (income)
Actuarial loss, before tax	22,387	32,247
Prior service cost (credit), before tax	719	$ (1,185)
Net actuarial loss expected to be amortized to net period benefit cost in next fiscal year	800
Prior service credit expected to be amortized to net periodic benefit cost in next fiscal year	$ 0