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 (Deficit) [Member]	Non-controlling Interest [Member]	Total
Balance at May. 31, 2017	$ 5	$ 2,836	$ 53,790,764	$ (53,724,991)	$ 68,614	$ 1,071,516	$ 1,140,130
Balance, shares at May. 31, 2017	50,000	28,361,201
Cash distributions						$ (233,400)	(233,400)
Preferred dividends				(384,384)	(384,384)		(384,384)
Net income				1,624,062	1,624,062	247,039	1,871,101
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