Note 6 - Investments in Joint Ventures - Condensed Income Statement of EXCOR and All Other Joint Ventures (Details) - USD ($)	3 Months Ended		9 Months Ended
	May 31, 2024	May 31, 2023	May 31, 2024	May 31, 2023
Net sales	$ 20,686,197	$ 20,969,726	$ 61,710,410	$ 59,193,317
Gross profit	7,893,094	7,579,853	23,566,532	20,236,045
Net income	976,604	1,059,590	3,573,294	1,973,329
NTIC’s share of equity in income from joint ventures	1,396,731	1,346,658	3,676,962	3,664,793
EXCOR and All Other Joint Venturs [Member]
Net income	2,793,738	2,692,444	7,351,372	7,308,398
NTIC’s share of equity in income from joint ventures	1,396,730	1,346,658	3,676,961	3,664,793
NTIC’s dividends received from joint ventures	567,674	45,977	2,958,925	3,510,716
EXCOR [Member]
Net income	1,623,431	1,654,151	4,029,182	4,761,608
NTIC’s share of equity in income from joint ventures	811,399	828,631	2,015,734	2,376,575
NTIC’s dividends received from joint ventures	0	0	1,624,950	2,459,500
All Other [Member]
Net income	1,170,307	1,038,293	3,322,190	2,546,790
NTIC’s share of equity in income from joint ventures	585,331	518,027	1,661,228	1,288,218
NTIC’s dividends received from joint ventures	567,674	45,977	1,333,975	1,051,216
EXCOR and All Other Joint Venturs [Member]
Net sales	25,602,072	26,312,548	72,642,714	76,525,427
Gross profit	10,713,282	10,494,244	30,956,162	30,223,623
EXCOR [Member]
Net sales	9,977,354	10,735,862	27,561,950	30,590,265
Gross profit	4,959,536	5,085,837	14,164,541	14,539,314
All Other [Member]
Net sales	15,624,718	15,576,686	45,080,764	45,935,162
Gross profit	$ 5,753,746	$ 5,408,407	$ 16,791,620	$ 15,684,309