Consolidated Statements of Changes in Equity - USD ($)	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Total Greystone Stockholders' Equity [Member]	Non-controlling Interest [Member]	Total
Balance at May. 31, 2018	$ 5	$ 2,836	$ 53,790,764	$ (52,485,313)	$ 1,308,292	$ 1,085,155	$ 2,393,447
Balance, shares at May. 31, 2018	50,000	28,361,201
Cash distributions						(211,000)	(211,000)
Preferred dividends				(428,455)	(428,455)		(428,455)
Net income				1,805,091	1,805,091	252,116	2,057,207
Balance at May. 31, 2019	$ 5	$ 2,836	53,790,764	(51,108,677)	2,684,928	1,126,271	3,811,199
Balance, shares at May. 31, 2019	50,000	28,361,201
Cash distributions						(215,400)	(215,400)
Preferred dividends				(398,836)	(398,836)		(398,836)
Net income				4,700,421	4,700,421	262,149	4,962,570
Balance at May. 31, 2020	$ 5	$ 2,836	$ 53,790,764	$ (46,807,092)	$ 6,986,513	$ 1,173,020	$ 8,159,533
Balance, shares at May. 31, 2020	50,000	28,361,201