Consolidated Statements of Income (Unaudited) - USD ($)	3 Months Ended
	Aug. 31, 2018	Aug. 31, 2017
Income Statement [Abstract]
Sales	$ 18,206,110	$ 10,287,075
Cost of Sales	15,760,152	8,388,176
Gross Profit	2,445,958	1,898,899
General, Selling and Administrative Expenses	939,091	831,403
Operating Income	1,506,867	1,067,496
Other Income (Expense):
Other income	2,269	8,263
Interest expense	(412,628)	(324,677)
Income before Income Taxes	1,096,508	751,082
Provision for Income Taxes	331,600	220,800
Net Income	764,908	530,282
Income Attributable to Non-controlling Interest	(60,575)	(61,053)
Preferred Dividends	(102,945)	(94,521)
Net Income Attributable to Common Stockholders	$ 601,388	$ 374,708
Income Per Share of Common Stock - Basic and Diluted	$ 0.02	$ 0.01
Weighted Average Shares of Common Stock Outstanding - Basic	28,361,201	28,361,201
Weighted Average Shares of Common Stock Outstanding - Diluted	29,003,696	28,979,740