Supplemental Cash Flow Data (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2015
Supplemental Cash Flow Data
Income taxes paid	$ 21,025	$ 17,550	$ 11,987
Interest paid	786	1,059	1,114
Common stock received for payment of stock option exercises	1,158	2,015	2,180
Property, plant & equipment additions included in accounts payable	220	22	53
Deferred tax assets and liabilities acquired from non-controlling interest			446
Resin Designs
Acquisition of certain assets
Current assets (excluding cash)	3,240
Property, plant and equipment	623
Goodwill and Intangible assets	(27,042)
Accounts payable and accrued liabilities	(635)
Payments for acquisitions, net of cash acquired	(30,270)
Spray Products Private Limited
Acquisition of certain assets
Current assets (excluding cash)		55
Property, plant and equipment		1,027
Goodwill		107
Accounts payable and accrued liabilities		(28)
Payments for acquisitions, net of cash acquired		(1,161)
Specialty chemical intermediates product line
Sale of business
Inventory			(610)
Acquisition of certain assets
Property, plant and equipment			1,064
Goodwill and Intangible assets			(31,611)
Payments for acquisitions, net of cash acquired			$ (33,285)
RodPack Business
Sale of business
Property and equipment		(846)
Intangible assets		(309)
Gain on sale of business		(1,031)
Due from sale of business (recorded within Other assets)	(457)	457
Cash received from sale of business, net of transaction costs	457	$ 1,729
Fiber Optic Cable Components Product Line
Sale of business
Inventory	(1,167)
Property and equipment	(166)
Goodwill and Intangible assets	512
Gain on sale of business	(2,013)
Due from sale of business (recorded within Other assets)	400
Cash received from sale of business, net of transaction costs	$ 3,458