Goodwill and Other Intangibles - Goodwill (Details) $ in Thousands	3 Months Ended			12 Months Ended
	Aug. 31, 2020 USD ($)	Aug. 31, 2019 USD ($) segment	Feb. 28, 2019 USD ($)	Aug. 31, 2020 USD ($) segment	Aug. 31, 2019 USD ($)
Changes in the carrying value of goodwill
Balance at the beginning of the period				$ 81,986	$ 84,696
Loss on impairment of polyurethane dispersions business	$ 0		$ (2,410)		(2,410)
Foreign currency translation adjustment				416	(300)
Balance at the end of the period	82,402	$ 81,986		$ 82,402	81,986
Number of reporting units | segment				3
Number of operating segments | segment		3		3
Goodwill deductible for income tax purposes	31,591	$ 34,778		$ 31,591	34,778
Adhesives, Sealants and Additives
Changes in the carrying value of goodwill
Balance at the beginning of the period				50,090	52,787
Loss on impairment of polyurethane dispersions business			$ (2,410)		(2,410)
Foreign currency translation adjustment				397	(287)
Balance at the end of the period	50,487	50,090		50,487	50,090
Industrial Tapes
Changes in the carrying value of goodwill
Balance at the beginning of the period				21,215	21,215
Balance at the end of the period	21,215	21,215		21,215	21,215
Corrosion Protection and Waterproofing
Changes in the carrying value of goodwill
Balance at the beginning of the period				10,681	10,694
Foreign currency translation adjustment				19	(13)
Balance at the end of the period	$ 10,700	$ 10,681		$ 10,700	$ 10,681