CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($)	Common Stock	Additional Paid In Capital	Unrealized Gain on Marketable securities [Member]	Retained Earnings	Common Stock Held in Treasury	Total
Balance at Jul. 31, 2017	$ 2,178,297	$ 3,346,245	$ 368,476	$ 45,395,245	$ 1,287,852	$ 50,000,411
Increase in unrealized gains on marketable securities			42,512			42,512
Net income/loss				3,167,496		3,167,496
Balance at Apr. 30, 2018	2,178,297	3,346,245	410,988	48,562,741	1,287,852	53,210,419
Increase in unrealized gains on marketable securities			76,148			76,148
Net income/loss				(193,355)		(193,355)
Balance at Jul. 31, 2018	2,178,297	3,346,245	487,136	48,369,386	1,287,852	53,093,212
Reclassification of unrealized gains on marketable securities to retained earnings (Note 1)			(487,136)	487,136
Net income/loss				870,701		870,701
Balance at Apr. 30, 2019	$ 2,178,297	$ 3,346,245		$ 49,727,223	$ 1,287,852	$ 53,963,913