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Marketable Securities (Details 2) - USD ($) $ in Thousands | Jul. 31, 2017 | Jul. 31, 2016
--- | --- | ---
Schedule of Available-for-sale Securities [Line Items] |  |
Unrealized Losses | $ 48 | $ 181
Fair Value | 19,081 | 10,716
Certificates of Deposit [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Unrealized Losses | 7 |
Fair Value | 12,155 |
Mutual funds [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Unrealized Losses |  | 39
Fair Value |  | 5,082
Federal Government Sponsored Enterprise notes [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Unrealized Losses | 14 |
Fair Value | 3,529 |
Equity [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Unrealized Losses | 26 | 140
Fair Value | 48 | 2,323
U.S. Treasury notes [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Unrealized Losses |  | 1
Fair Value |  | 199
Municipal bonds [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Unrealized Losses | 1 | 1
Fair Value | $ 3,349 | $ 3,112

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