Fair Value Measurements (Details) - USD ($) $ in Thousands	Jan. 31, 2020	Jul. 31, 2019
Available-for-sale securities:
Hedge Funds	$ 5,645	$ 5,125
Total	5,645	5,125
Level 1 [Member]
Available-for-sale securities:
Hedge Funds
Total
Level 2 [Member]
Available-for-sale securities:
Hedge Funds
Total
Level 3 [Member]
Available-for-sale securities:
Hedge Funds	5,645	5,125
Total	$ 5,645	$ 5,125