Other Assets - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2016	Aug. 31, 2015	Aug. 31, 2014
Goodwill [Line Items]
Goodwill, Acquired During Period	$ 9,774	$ 423
Amortization of intangible assets	6,100	7,300	$ 9,700
Goodwill, Written off Related to Sale of Business Unit	695
Ag [Member]
Goodwill [Line Items]
Goodwill, Acquired During Period	5,726
Finite-lived intangible assets acquired	2,800	800
Goodwill, Written off Related to Sale of Business Unit	695
Series of Individually Immaterial Business Acquisitions [Member]
Goodwill [Line Items]
Payments to Acquire Assets, Investing Activities	$ 50,300	321,000	$ 281,500
Minimum | Other Intangible Assets [Member]
Goodwill [Line Items]
Finite-Lived Intangible Asset, Useful Life	2 years
Minimum | Major Maintenance Activities Requiring Shutdown
Goodwill [Line Items]
Finite-Lived Intangible Asset, Useful Life	2 years
Maximum | Other Intangible Assets [Member]
Goodwill [Line Items]
Finite-Lived Intangible Asset, Useful Life	30 years
Maximum | Major Maintenance Activities Requiring Shutdown
Goodwill [Line Items]
Finite-Lived Intangible Asset, Useful Life	4 years
Cash Distribution [Member] | Series of Individually Immaterial Business Acquisitions [Member]
Goodwill [Line Items]
Payments to Acquire Assets, Investing Activities	$ 11,900	$ 305,200