Consolidated Statements of Changes in Equity (Unaudited) - 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						(51,000)	(51,000)
Preferred dividends				(102,945)	(102,945)		(102,945)
Net income				704,333	704,333	60,575	764,908
Balance at Aug. 31, 2018	$ 5	$ 2,836	53,790,764	(51,883,925)	1,909,680	1,094,730	3,004,410
Balance, shares at Aug. 31, 2018	50,000	28,361,201
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
Net income							1,293,283
Balance at Feb. 28, 2019	$ 5	$ 2,836	53,790,764	(51,695,914)	2,097,691	1,119,775	3,217,466
Balance, shares at Feb. 28, 2019	50,000	28,361,201
Balance at Aug. 31, 2018	$ 5	$ 2,836	53,790,764	(51,883,925)	1,909,680	1,094,730	3,004,410
Balance, shares at Aug. 31, 2018	50,000	28,361,201
Cash distributions						(51,000)	(51,000)
Preferred dividends				(105,100)	(105,100)		(105,100)
Net income				233,993	233,993	62,952	296,945
Balance at Nov. 30, 2018	$ 5	$ 2,836	53,790,764	(51,755,032)	2,038,573	1,106,682	3,145,255
Balance, shares at Nov. 30, 2018	50,000	28,361,201
Cash distributions						(51,000)	(51,000)
Preferred dividends				(108,219)	(108,219)		(108,219)
Net income				167,337	167,337	64,093	231,430
Balance at Feb. 28, 2019	$ 5	$ 2,836	53,790,764	(51,695,914)	2,097,691	1,119,775	3,217,466
Balance, shares at Feb. 28, 2019	50,000	28,361,201
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						(52,200)	(52,200)
Preferred dividends				(112,363)	(112,363)		(112,363)
Net income				554,613	554,613	64,686	619,299
Balance at Aug. 31, 2019	$ 5	$ 2,836	53,790,764	(50,666,427)	3,127,178	1,138,757	4,265,935
Balance, shares at Aug. 31, 2019	50,000	28,361,201
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
Net income							3,056,926
Balance at Feb. 29, 2020	$ 5	$ 2,836	53,790,764	(48,562,194)	5,231,411	1,158,788	6,390,199
Balance, shares at Feb. 29, 2020	50,000	28,361,201
Balance at Aug. 31, 2019	$ 5	$ 2,836	53,790,764	(50,666,427)	3,127,178	1,138,757	4,265,935
Balance, shares at Aug. 31, 2019	50,000	28,361,201
Cash distributions						(69,600)	(69,600)
Preferred dividends				(102,637)	(102,637)		(102,637)
Net income				407,065	407,065	65,620	472,685
Balance at Nov. 30, 2019	$ 5	$ 2,836	53,790,764	(50,361,999)	3,431,606	1,134,777	4,566,383
Balance, shares at Nov. 30, 2019	50,000	28,361,201
Cash distributions						(41,400)	(41,400)
Preferred dividends				(99,726)	(99,726)		(99,726)
Net income				1,899,531	1,899,531	65,411	1,964,942
Balance at Feb. 29, 2020	$ 5	$ 2,836	$ 53,790,764	$ (48,562,194)	$ 5,231,411	$ 1,158,788	$ 6,390,199
Balance, shares at Feb. 29, 2020	50,000	28,361,201