Consolidated Statements of Income (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Nov. 30, 2019	Nov. 30, 2018	Nov. 30, 2019	Nov. 30, 2018
Income Statement [Abstract]
Sales	$ 19,503,462	$ 14,733,130	$ 38,167,971	$ 32,939,240
Cost of Sales	17,353,239	13,041,366	33,656,973	28,801,518
Gross Profit	2,150,223	1,691,764	4,510,998	4,137,722
Selling, General and Administrative Expenses	1,112,630	853,650	2,190,228	1,792,741
Operating Income	1,037,593	838,114	2,320,770	2,344,981
Other Income (Expense):
Other income	2,880	3,021	4,913	5,290
Interest expense	(432,788)	(435,690)	(913,699)	(848,318)
Income before Income Taxes	607,685	405,445	1,411,984	1,501,953
Provision for Income Taxes	135,000	108,500	320,000	440,100
Net Income	472,685	296,945	1,091,984	1,061,853
Income Attributable to Non-controlling Interest	(65,620)	(62,952)	(130,306)	(123,527)
Preferred Dividends	(102,637)	(105,100)	(215,000)	(208,045)
Net Income Attributable to Common Stockholders	$ 304,428	$ 128,893	$ 746,678	$ 730,281
Income Per Share of Common Stock - Basic and Diluted	$ 0.01	$ 0.00	$ 0.03	$ 0.03
Weighted Average Shares of Common Stock Outstanding - Basic	28,361,201	28,361,201	28,361,201	28,361,201
Weighted Average Shares of Common Stock Outstanding - Diluted	29,001,160	29,018,262	29,005,432	29,009,949