CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) |
Apr. 30, 2018 |
Jul. 31, 2017 |
|---|---|---|
| Common stock, par value | $ 1 | $ 1 |
| Common stock, shares authorized | 5,000,000 | 5,000,000 |
| Common stock, shares issued | 2,178,297 | 2,178,297 |
| Treasury stock, shares | 162,517 | 162,517 |
| Unrealized Gain on Available-for-sale Securities - Net of Deferred Taxes [Member] | ||
| Unrealized gain (loss) on available-for-sale securities, deferred taxes (benefit) | $ 226,000 | $ 190,000 |