Other Assets - Schedule of Goodwill (Details) - USD ($)		3 Months Ended	12 Months Ended
	Jul. 31, 2018	May 31, 2017	Aug. 31, 2018	Aug. 31, 2017
Goodwill [Roll Forward]
Balances, beginning of period			$ 138,454,000	$ 144,284,000
Effect of foreign currency translation adjustments			10,000	352,000
Impairment	$ 0	$ (5,500,000)		(5,542,000)
Other			0	(640,000)
Balances, end of period			138,464,000	138,454,000
Energy
Goodwill [Roll Forward]
Balances, beginning of period			552,000	552,000
Effect of foreign currency translation adjustments			0	0
Impairment				0
Other			0	0
Balances, end of period			552,000	552,000
Ag
Goodwill [Roll Forward]
Balances, beginning of period			127,328,000	132,786,000
Effect of foreign currency translation adjustments			10,000	352,000
Impairment				(5,542,000)
Other			0	(268,000)
Balances, end of period			127,338,000	127,328,000
Corporate and Other
Goodwill [Roll Forward]
Balances, beginning of period			10,574,000	10,946,000
Effect of foreign currency translation adjustments			0	0
Impairment				0
Other			0	(372,000)
Balances, end of period			$ 10,574,000	10,574,000
As Previously Reported
Goodwill [Roll Forward]
Balances, beginning of period				160,414,000
As Previously Reported | Energy
Goodwill [Roll Forward]
Balances, beginning of period				552,000
As Previously Reported | Ag
Goodwill [Roll Forward]
Balances, beginning of period				148,916,000
As Previously Reported | Corporate and Other
Goodwill [Roll Forward]
Balances, beginning of period				10,946,000
Restatement Adjustments
Goodwill [Roll Forward]
Balances, beginning of period				(16,130,000)
Restatement Adjustments | Energy
Goodwill [Roll Forward]
Balances, beginning of period				0
Restatement Adjustments | Ag
Goodwill [Roll Forward]
Balances, beginning of period				(16,130,000)
Restatement Adjustments | Corporate and Other
Goodwill [Roll Forward]
Balances, beginning of period				$ 0