Consolidated Statements of Comprehensive Income Parenthetical - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2015
Other Comprehensive Income [Abstract]
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	$ 18,688	$ 3,903	$ (12,726)
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	2,732	947	(154)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	1,392	(2,410)	(1,607)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	$ 214	$ 1,163	$ 4,057