Commitments and Contingencies - Purchase Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2016	Aug. 31, 2015	Aug. 31, 2014
Unrecorded Unconditional Purchase Obligation [Line Items]
Long-term unconditional purchase obligations, minimum amount required	$ 627,200
Long-term unconditional purchase obligations, period amount purchase	88,000	$ 66,800	$ 65,500
Minimum
Unrecorded Unconditional Purchase Obligation [Line Items]
Long-term unconditional purchase obligations, Total	767,943
Long-term unconditional purchase obligations, Less than 1 Year	60,655
Long-term unconditional purchase obligations, 1 - 3 Years	108,120
Long-term unconditional purchase obligations, 3 - 5 Years	113,553
Long-term unconditional purchase obligations, More than 5 Years	$ 485,615