Note 6 - Investments in Joint Ventures - Condensed Balance Sheet of EXCOR and All Other Joint Ventures (Details) - USD ($)	Aug. 31, 2024	Aug. 31, 2023
Current assets	$ 41,579,219	$ 39,671,556
Total assets	94,676,502	89,344,303
Current liabilities	17,896,943	16,721,372
Noncurrent liabilities	1,604,238	1,924,134
Joint ventures’ equity	71,193,991	66,356,273
Investments in joint ventures	25,397,287	23,705,714
EXCOR and All Other Joint Ventures [Member]
Investments in joint ventures	25,397,287	23,705,714
NTIC’s share of joint ventures’ undistributed earnings	23,645,685	20,493,861
EXCOR [Member]
Investments in joint ventures	14,645,783	13,683,608
NTIC’s share of joint ventures’ undistributed earnings	14,614,878	12,075,524
All Other [Member]
Investments in joint ventures	10,751,504	10,022,106
NTIC’s share of joint ventures’ undistributed earnings	9,030,807	8,418,337
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member]
Current assets	56,420,503	55,339,662
Total assets	64,183,071	59,729,348
Current liabilities	12,553,716	11,464,247
Noncurrent liabilities	323,199	323,762
Joint ventures’ equity	51,306,156	47,941,339
EXCOR [Member]
Current assets	26,234,664	27,862,458
Total assets	31,513,288	30,054,277
Current liabilities	2,221,726	2,687,064
Noncurrent liabilities	0	0
Joint ventures’ equity	29,291,562	27,367,213
All Other [Member]
Current assets	30,185,839	27,477,204
Total assets	32,669,783	29,675,071
Current liabilities	10,331,990	8,777,183
Noncurrent liabilities	323,199	323,762
Joint ventures’ equity	$ 22,014,594	$ 20,574,126