Accumulated Other Comprehensive Income (Details) - USD ($)	3 Months Ended		6 Months Ended	9 Months Ended
	May 31, 2018	May 31, 2017	Aug. 31, 2018	May 31, 2018	May 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance				$ 2,368,344,000
Other comprehensive (loss) income before reclassifications				286,000
Amounts reclassified from AOCI				(28,974,000)
Total other comprehensive (loss) income	$ (60,676,000)	$ 24,606,000		(28,688,000)	$ 55,804,000
Ending Balance	2,185,558,000			2,185,558,000
Net tax benefit (expense) of foreign currency translation adjustment component of accumulated other comprehensive income	0			0
Net tax benefit (expense) of available for sale securities component of accumulated other comprehensive income	0			0
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance				57,582,000
Other comprehensive (loss) income before reclassifications				(19,720,000)
Amounts reclassified from AOCI				0
Total other comprehensive (loss) income				(19,720,000)
Ending Balance	37,862,000			37,862,000
Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance				29,967,000
Other comprehensive (loss) income before reclassifications				22,453,000
Amounts reclassified from AOCI				(28,974,000)
Total other comprehensive (loss) income				(6,521,000)
Ending Balance	23,446,000			23,446,000
Actuarial (Loss) Gain
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance				(33,215,000)
Other comprehensive (loss) income before reclassifications				(431,000)
Amounts reclassified from AOCI				0
Total other comprehensive (loss) income				(431,000)
Ending Balance	(33,646,000)			(33,646,000)
Prior Service Cost
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance				889,000
Other comprehensive (loss) income before reclassifications				0
Amounts reclassified from AOCI				0
Total other comprehensive (loss) income				0
Ending Balance	889,000			889,000
Available for Sale Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance				(603,000)
Other comprehensive (loss) income before reclassifications				(2,016,000)
Amounts reclassified from AOCI				0
Total other comprehensive (loss) income				(2,016,000)
Ending Balance	(2,619,000)			(2,619,000)
AOCI Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance				54,620,000
Ending Balance	$ 25,932,000			25,932,000
Income Tax Expense | Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI				$ 10,000,000
Scenario, Forecast | Income Tax Expense | Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI			$ 4,800,000