Consolidated Statements of Income (Unaudited) - USD ($)	3 Months Ended
	Aug. 31, 2019	Aug. 31, 2018
Income Statement [Abstract]
Sales	$ 18,664,509	$ 18,206,110
Cost of Sales	16,303,734	15,760,152
Gross Profit	2,360,775	2,445,958
General, Selling and Administrative Expenses	1,077,598	939,091
Operating Income	1,283,177	1,506,867
Other Income (Expense):
Other income	2,033	2,269
Interest expense	(480,911)	(412,628)
Income before Income Taxes	804,299	1,096,508
Provision for Income Taxes	185,000	331,600
Net Income	619,299	764,908
Income Attributable to Non-controlling Interest	(64,686)	(60,575)
Preferred Dividends	(112,363)	(102,945)
Net Income Attributable to Common Stockholders	$ 442,250	$ 601,388
Income Per Share of Common Stock - Basic and Diluted	$ 0.02	$ 0.02
Weighted Average Shares of Common Stock Outstanding - Basic	28,361,201	28,361,201
Weighted Average Shares of Common Stock Outstanding -Diluted	29,010,546	29,003,696