Consolidated Statements of Income (Unaudited) - USD ($)	3 Months Ended		9 Months Ended
	Feb. 29, 2020	Feb. 28, 2019	Feb. 29, 2020	Feb. 28, 2019
Income Statement [Abstract]
Sales	$ 19,738,806	$ 17,224,467	$ 57,906,777	$ 50,163,707
Cost of Sales	15,622,931	15,455,920	49,279,904	44,257,438
Gross Profit	4,115,875	1,768,547	8,626,873	5,906,269
Selling, General and Administrative Expenses	1,248,196	959,288	3,438,424	2,752,029
Operating Income	2,867,679	809,259	5,188,449	3,154,240
Other Income (Expense):
Other income	4,391	2,438	9,304	7,728
Interest expense	(420,128)	(499,967)	(1,333,827)	(1,348,285)
Income before Income Taxes	2,451,942	311,730	3,863,926	1,813,683
Provision for Income Taxes	487,000	80,300	807,000	520,400
Net Income	1,964,942	231,430	3,056,926	1,293,283
Income Attributable to Non-controlling Interest	(65,411)	(64,093)	(195,717)	(187,620)
Preferred Dividends	(99,726)	(108,219)	(314,726)	(316,264)
Net Income Attributable to Common Stockholders	$ 1,799,805	$ 59,118	$ 2,546,483	$ 789,399
Income Per Share of Common Stock - Basic and Diluted	$ 0.06	$ 0.00	$ 0.09	$ 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	28,999,499	29,012,048	29,003,201	29,009,415