Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Aug. 31, 2017	May 31, 2017	Feb. 28, 2017	Nov. 30, 2016	Aug. 31, 2016	May 31, 2016	Feb. 29, 2016	Nov. 30, 2015	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2015
Selected Quarterly Financial Data (Unaudited)
Net Sales	$ 67,679	$ 63,641	$ 56,288	$ 60,269	$ 60,518	$ 63,480	$ 53,706	$ 56,746	$ 247,877	$ 234,450	$ 234,890
Gross Profit on Sales	27,301	26,130	23,430	24,980	24,234	24,938	18,811	22,029	101,841	90,012
Net income attributable to Chase Corporation	$ 11,413	$ 11,855	$ 8,383	$ 10,363	$ 10,855	$ 7,531	$ 6,972	$ 7,449	$ 42,014	$ 32,807	$ 26,318
Net income available to common shareholders, per common and common equivalent share:
Basic (in dollars per share)	$ 1.22	$ 1.27	$ 0.90	$ 1.11	$ 1.17	$ 0.81	$ 0.75	$ 0.81	$ 4.49	$ 3.55	$ 2.87
Diluted (in dollars per share)	$ 1.21	$ 1.26	$ 0.89	$ 1.10	$ 1.16	$ 0.80	$ 0.74	$ 0.80	$ 4.44	$ 3.50	$ 2.82