Consolidated Statements of Income - USD ($)	12 Months Ended
	May 31, 2018	May 31, 2017
Income Statement [Abstract]
Sales	$ 48,609,075	$ 40,044,110
Cost of Sales	41,570,319	32,573,570
Gross Profit	7,038,756	7,470,540
General, Selling and Administrative Expenses	3,034,027	3,015,960
Operating Income	4,004,729	4,454,580
Other Income (Expense):
Other income	12,144	17,175
Interest expense	(1,373,392)	(1,212,857)
Income before Income Taxes	2,643,481	3,258,898
Provision for Income Taxes	772,380	1,011,990
Net Income	1,871,101	2,246,908
Income Attributable to Non-controlling Interest	(247,039)	(240,165)
Preferred Dividends	(384,384)	(345,822)
Net Income Attributable to Common Stockholders	$ 1,239,678	$ 1,660,921
Income Per Share of Common Stock - Basic and Diluted	$ 0.04	$ 0.06
Weighted Average Shares of Common Stock Outstanding - Basic	28,361,201	28,322,160
Weighted Average Shares of Common Stock Outstanding - Diluted	28,993,110	28,906,086