Note 9 - Net Income Per Common Share - Reconciliation of the Earnings Per Share Computations (Details) - USD ($)	3 Months Ended		6 Months Ended
	Feb. 28, 2019	Feb. 28, 2018	Feb. 28, 2019	Feb. 28, 2018
Net income attributable to NTIC	$ 1,401,568	$ 1,332,847	$ 2,898,627	$ 2,416,473
Basic – weighted shares outstanding (in shares)	4,542,177	4,537,408	4,542,175	4,537,368
Weighted shares assumed upon exercise of stock options (in shares)	181,753	135,930	189,433	103,674
Diluted – weighted shares outstanding (in shares)	4,723,930	4,673,338	4,731,608	4,641,042
Basic net income per share: (in dollars per share)	$ 0.31	$ 0.29	$ 0.64	$ 0.53
Diluted net income per share: (in dollars per share)	$ 0.30	$ 0.29	$ 0.61	$ 0.52