Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Operating Loss Carryforwards [Line Items]
Provisional Income Tax Expense Resulting from Changes in Tax Legislation (repatriation)	$ 3,327
Provisional Income Tax Expense Resulting from Changes in Tax Legislation (net of other disclosures)	16,761
Unrecognized Tax Benefits	$ 20,430	$ 18,362	$ 15,294	$ 21,133
Foreign Net Operating Loss Carryforwards Expiration Dates	five years
State Net Operating Loss Carryforwards Expiration Dates	2022 to 2038
Foreign Tax Credit Carryforward Expiration Dates	2021 to 2027
State Research And Development Tax Credit Carryforward Expiration Dates	2019 to 2033
Unrecognized Tax Benefits, Interest on Income Taxes Expense	$ 556	674	3
Unrecognized Tax Benefits, Income Tax Penalties Expense	83	218	66
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	2,762	2,239
Unrecognized Tax Benefits, Income Tax Penalties Accrued	3,027	2,948
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	9,686
Unrecognized Tax Benefits Recognized In Other Liabilities	13,238	11,725
Reduction Of Longterm Deferred Income Tax Assets Excluding Interest and Penalties	7,192	6,637
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations	675
Cash and cash equivalents	181,427	$ 133,944	$ 141,228	$ 114,492
Provisional Income Tax Expense Resulting from Changes in Tax Legislation (APB 23)	984
Foreign Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	108,540
Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration	88,197
Other Tax Carryforward, Gross Amount	25,115
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	35,231
Other Tax Carryforward, Gross Amount	11,448
Maximum recorded through earnings [Member]
Operating Loss Carryforwards [Line Items]
Unrecognized Tax Benefits, Income Tax Penalties Accrued	$ 9,686
United States, Federal [Member] | Low end of range [Member]
Operating Loss Carryforwards [Line Items]
Open Tax Year	2015
United States, Federal [Member] | High end of range [Member]
Operating Loss Carryforwards [Line Items]
Open Tax Year	2018
FRANCE | Low end of range [Member]
Operating Loss Carryforwards [Line Items]
Open Tax Year	2015
FRANCE | High end of range [Member]
Operating Loss Carryforwards [Line Items]
Open Tax Year	2018