Goodwill and Other Intangible Assets Goodwill by Segment (Details) $ in Thousands	6 Months Ended
	Feb. 28, 2018 USD ($)
Goodwill [Roll Forward]
Beginning Balance, Goodwill	$ 154,055
Effect of foreign currency translation adjustments	(277)
Ending Balance, Goodwill	153,778
Energy [Member]
Goodwill [Roll Forward]
Beginning Balance, Goodwill	552
Effect of foreign currency translation adjustments	0
Ending Balance, Goodwill	552
Ag [Member]
Goodwill [Roll Forward]
Beginning Balance, Goodwill	142,929
Effect of foreign currency translation adjustments	(277)
Ending Balance, Goodwill	142,652
Corporate and Other
Goodwill [Roll Forward]
Beginning Balance, Goodwill	10,574
Effect of foreign currency translation adjustments	0
Ending Balance, Goodwill	10,574
Nitrogen Production [Member]
Goodwill [Roll Forward]
Ending Balance, Goodwill	$ 0