Goodwill and Other Intangible Assets Goodwill by Segment (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	May 31, 2017	May 31, 2017
Goodwill [Roll Forward]
Beginning Balance, Goodwill		$ 160,414
Effect of foreign currency translation adjustments		(868)
Goodwill, Impairment Loss	$ (5,500)	(5,542)
Other		(670)
Ending Balance, Goodwill	153,334	153,334
Energy [Member]
Goodwill [Roll Forward]
Beginning Balance, Goodwill		552
Effect of foreign currency translation adjustments		0
Goodwill, Impairment Loss		0
Other		0
Ending Balance, Goodwill	552	552
Ag [Member]
Goodwill [Roll Forward]
Beginning Balance, Goodwill		148,916
Effect of foreign currency translation adjustments		(868)
Goodwill, Impairment Loss		(5,542)
Other		(298)
Ending Balance, Goodwill	142,208	142,208
Corporate and Other
Goodwill [Roll Forward]
Beginning Balance, Goodwill		10,946
Effect of foreign currency translation adjustments		0
Goodwill, Impairment Loss		0
Other		(372)
Ending Balance, Goodwill	10,574	10,574
Nitrogen Production [Member]
Goodwill [Roll Forward]
Ending Balance, Goodwill	0	0
Foods [Member]
Goodwill [Roll Forward]
Ending Balance, Goodwill	$ 0	$ 0