Note 7 - Investments in Joint Ventures - Condensed Income Statement of EXCOR and All Other Joint Ventures (Details) - USD ($)	3 Months Ended		9 Months Ended
	May 31, 2025	May 31, 2024	May 31, 2025	May 31, 2024
Net sales	$ 21,508,563	$ 20,686,197	$ 61,919,022	$ 61,710,410
Gross profit	8,259,440	7,893,094	23,217,977	23,566,532
Net income	121,775	976,604	1,117,185	3,573,294
NTIC’s share of equity in income from joint ventures	970,314	1,396,731	2,720,637	3,676,962
EXCOR and All Other Joint Venturs [Member]
Net income	1,937,620	2,793,738	5,416,777	7,351,372
NTIC’s share of equity in income from joint ventures	970,314	1,396,730	2,720,637	3,676,961
NTIC’s dividends received from joint ventures	886,209	567,674	1,566,946	2,958,925
EXCOR [Member]
Net income	897,104	1,623,431	2,665,391	4,029,182
NTIC’s share of equity in income from joint ventures	448,673	811,399	1,340,674	2,015,734
NTIC’s dividends received from joint ventures	0	0	0	1,624,950
All Other [Member]
Net income	1,040,516	1,170,307	2,751,386	3,322,190
NTIC’s share of equity in income from joint ventures	521,641	585,331	1,379,963	1,661,227
NTIC’s dividends received from joint ventures	886,209	567,674	1,566,946	1,333,975
EXCOR and All Other Joint Venturs [Member]
Net sales	23,211,613	25,602,072	66,848,498	72,642,714
Gross profit	9,768,978	10,713,282	28,325,377	30,956,162
EXCOR [Member]
Net sales	8,271,661	9,977,354	23,914,520	27,561,950
Gross profit	4,339,777	4,959,536	12,695,626	14,164,541
All Other [Member]
Net sales	14,939,952	15,624,718	42,933,978	45,080,764
Gross profit	$ 5,429,201	$ 5,753,746	$ 15,629,751	$ 16,791,621