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Fair Value Measurements (Details) - USD ($) $ in Thousands | Oct. 31, 2018 | Jul. 31, 2018
--- | --- | ---
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Debt securities |  | $ 2,237 | $ 5,612
Equity securities included in other current assets |  | 292 | 360
Equity securities included in equity investments |  | 2,816 |
Total |  | 5,345 | 5,972
Fair Value Measurements, Recurring basis [Member] | Level 1 [Member] |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Debt securities | [1] | 1,695 | 1,692
Equity securities included in other current assets | [1] | 292 | 360
Equity securities included in equity investments | [1] |  |
Total | [1] | 1,987 | 2,052
Fair Value Measurements, Recurring basis [Member] | Level 2 [Member] |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Debt securities | [2] | 542 | 3,920
Equity securities included in other current assets | [2] |  |
Equity securities included in equity investments | [2] |  |
Total | [2] | 542 | 3,920
Fair Value Measurements, Recurring basis [Member] | Level 3 [Member] |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Debt securities | [3] |  |
Equity securities included in other current assets | [3] |  |
Equity securities included in equity investments | [3] | 2,816 |
Total | [3] | $ 2,816 |
[1] | quoted prices in active markets for identical assets or liabilities
[2] | observable inputs other than quoted prices in active markets for identical assets and liabilities
[3] | no observable pricing inputs in the market

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