Consolidated Statements of Changes in Deficit - USD ($)	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Total Greystone Stockholders' Deficit [Member]	Non-controlling Interest [Member]	Total
Balance at May. 31, 2014	$ 5	$ 2,646	$ 53,336,106	$ (55,715,203)	$ (2,376,446)	$ 993,123	$ (1,383,323)
Balance, Shares at May. 31, 2014	50,000	26,461,201
Common stock options exercised		$ 95	113,905		114,000		$ 114,000
Common stock options exercised, Shares		950,000					(950,000)
Stock based compensation			53,424		53,424		$ 53,424
Cash distributions						(204,000)	(204,000)
Preferred dividends				(325,000)	(325,000)		(325,000)
Net income				382,565	382,565	227,004	609,569
Balance at May. 31, 2015	$ 5	$ 2,741	53,503,435	(55,657,638)	(2,151,457)	1,016,127	(1,135,330)
Balance, Shares at May. 31, 2015	50,000	27,411,201
Common stock options exercised		$ 48	56,952		57,000		$ 57,000
Common stock options exercised, Shares		475,000					(475,000)
Stock based compensation			53,424		53,424		$ 53,424
Cash distributions						(204,000)	(204,000)
Preferred dividends				(331,575)	(331,575)		(331,575)
Net income				603,301	603,301	232,833	836,134
Balance at May. 31, 2016	$ 5	$ 2,789	$ 53,613,811	$ (55,385,912)	$ (1,769,307)	$ 1,044,960	$ (724,347)
Balance, Shares at May. 31, 2016	50,000	27,886,201