Goodwill and Other Intangibles - By Class (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	May 31, 2017	May 31, 2016	Aug. 31, 2016
Goodwill and intangible assets
Gross Carrying Value	$ 88,933		$ 69,932
Accumulated Amortization	39,795		33,352
Net Carrying Value	49,138		$ 36,580
Aggregate amortization expense	6,816	$ 5,774
Estimated amortization expense
2017 (remaining 3 months)	2,297
2018	9,152
2019	8,459
2020	7,586
2021	7,042
2022	$ 6,163
Patents and agreements
Goodwill and intangible assets
Weighted-Average Amortization Period	14 years 6 months		14 years 6 months
Gross Carrying Value	$ 1,816		$ 1,805
Accumulated Amortization	1,669		1,663
Net Carrying Value	$ 147		$ 142
Formulas and technology
Goodwill and intangible assets
Weighted-Average Amortization Period	7 years 9 months 18 days		8 years 4 months 24 days
Gross Carrying Value	$ 9,312		$ 8,248
Accumulated Amortization	5,079		4,310
Net Carrying Value	$ 4,233		$ 3,938
Trade names
Goodwill and intangible assets
Weighted-Average Amortization Period	6 years		5 years 10 months 24 days
Gross Carrying Value	$ 7,704		$ 7,137
Accumulated Amortization	5,548		4,909
Net Carrying Value	$ 2,156		$ 2,228
Customer lists and relationships
Goodwill and intangible assets
Weighted-Average Amortization Period	9 years 7 months 6 days		9 years 4 months 24 days
Gross Carrying Value	$ 70,101		$ 52,742
Accumulated Amortization	27,499		22,470
Net Carrying Value	$ 42,602		$ 30,272