Note 7 - Investments in Joint Ventures - Condensed Balance Sheet of EXCOR and All Other Joint Ventures (Details) - USD ($)	May 31, 2025	Aug. 31, 2024
Current assets	$ 42,600,386	$ 41,579,219
Total assets	99,303,381	94,676,502
Current liabilities	20,938,671	17,896,943
Non-current liabilities	1,788,215	1,604,238
Joint ventures’ equity	72,355,000	71,193,991
Investments in joint ventures	27,139,197	25,397,287
EXCOR and All Other Joint Venturs [Member]
Investments in joint ventures	27,139,197	25,397,287
NTIC’s share of joint ventures’ undistributed earnings	24,096,958	23,645,685
EXCOR [Member]
Investments in joint ventures	16,441,653	14,645,783
NTIC’s share of joint ventures’ undistributed earnings	14,613,903	14,614,878
All Other [Member]
Investments in joint ventures	10,697,544	10,751,504
NTIC’s share of joint ventures’ undistributed earnings	9,483,055	9,030,807
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member]
Current assets	57,530,046	56,420,503
Total assets	67,124,813	64,183,071
Current liabilities	12,049,553	12,553,716
Non-current liabilities	285,249	323,199
Joint ventures’ equity	54,790,011	51,306,156
EXCOR [Member]
Current assets	27,868,655	26,234,664
Total assets	34,923,270	31,513,288
Current liabilities	2,039,968	2,221,726
Non-current liabilities	0	0
Joint ventures’ equity	32,883,302	29,291,562
Joint Ventures in France [Member]
Current assets		30,185,839
Total assets		32,669,783
Current liabilities		10,331,990
Non-current liabilities		323,199
Joint ventures’ equity		$ 22,014,594
All Other [Member]
Current assets	29,661,391
Total assets	32,201,543
Current liabilities	10,009,585
Non-current liabilities	285,249
Joint ventures’ equity	$ 21,906,709