Goodwill and Other Intangibles - Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2015
Goodwill and intangible assets
Gross Carrying Value	$ 89,052	$ 69,932
Accumulated Amortization	42,206	33,352
Net Carrying Value	46,846	36,580
Aggregate amortization expense	9,127	$ 7,836	$ 6,762
Estimated amortization expense
2018	9,110
2019	8,441
2020	7,574
2021	7,044
2022	$ 6,164
Patents and agreements
Goodwill and intangible assets
Weighted-Average Amortization Period	14 years 4 months 24 days	14 years 6 months
Gross Carrying Value	$ 1,845	$ 1,805
Accumulated Amortization	1,671	1,663
Net Carrying Value	$ 174	$ 142
Formulas
Goodwill and intangible assets
Weighted-Average Amortization Period	7 years 9 months 18 days	8 years 4 months 24 days
Gross Carrying Value	$ 9,318	$ 8,248
Accumulated Amortization	5,387	4,310
Net Carrying Value	$ 3,931	$ 3,938
Trade names
Goodwill and intangible assets
Weighted-Average Amortization Period	6 years	5 years 10 months 24 days
Gross Carrying Value	$ 7,709	$ 7,137
Accumulated Amortization	5,813	4,909
Net Carrying Value	$ 1,896	$ 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	$ 70,180	$ 52,742
Accumulated Amortization	29,335	22,470
Net Carrying Value	$ 40,845	$ 30,272