Revenue - Narrative (Details) - USD ($)	3 Months Ended
Oct. 31, 2018	Oct. 31, 2017
Concentration Risk [Line Items]
Revenue recognized	$ 23,127,000
Remaining performance obligation, amount	$ 627,252,000
Sales Revenue, Net \| Verizon Communications Inc. \| Major customer
Concentration Risk [Line Items]
Percentage of revenue generated from external customer type		11.70%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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Amount of transaction price allocated to performance obligation that has not been recognized as revenue.

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