Commitments and Contingencies - Purchase Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2015	Aug. 31, 2014	Aug. 31, 2013
Unrecorded Unconditional Purchase Obligation [Line Items]
Long-term unconditional purchase obligations, minimum amount required	$ 655,000
Long-term unconditional purchase obligations, period amount purchase	66,800	$ 65,500	$ 62,400
Minimum
Unrecorded Unconditional Purchase Obligation [Line Items]
Long-term unconditional purchase obligations, Total	815,179
Long-term unconditional purchase obligations, Less than 1 Year	62,585
Long-term unconditional purchase obligations, 1 - 3 Years	111,905
Long-term unconditional purchase obligations, 3 - 5 Years	109,712
Long-term unconditional purchase obligations, More than 5 Years	$ 530,977