Fair Value Measurements - Schedule of Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($)	Dec. 31, 2020	Jun. 30, 2020
Investment in marketable securities	$ 714,000	$ 870,000
Level 1 [Member]
Investment in marketable securities	714,000	870,000
Basic Materials [Member] | Level 1 [Member]
Investment in marketable securities	431,000	575,000
REITs and Real Estate Companies [Member] | Level 1 [Member]
Investment in marketable securities	283,000	253,000
Industrials [Member] | Level 1 [Member]
Investment in marketable securities		3,000
Energy [Member] | Level 1 [Member]
Investment in marketable securities		$ 39,000