Income Taxes - Reconciliation (Details)	9 Months Ended	12 Months Ended
Jul. 31, 2018	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Expected statutory tax	26.90%	21.00%	21.00%	26.90%
Differential attributable to:
Foreign operations		16.00%	0.30%	0.60%
State and local taxes		13.70%	4.80%	3.70%
U.S. permanent items		5.30%	1.90%	(1.50%)
Tax reserves		11.30%	0.00%	0.00%
U.S Federal tax legislation		(156.30%)	(0.10%)	(7.40%)
R&E tax credit		(26.90%)	(1.00%)	(0.70%)
U.S. foreign inclusions		(2.90%)	(0.80%)	0.00%
Excess tax benefits		6.90%	(0.70%)	(1.70%)
Valuation allowance		16.80%	0.10%	2.40%
Other		(2.10%)	1.40%	0.20%
Consolidated effective tax rate		(97.20%)	26.90%	22.50%

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Effective Income Tax Reconciliation, Legislature Changes

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the valuation allowance for deferred tax assets.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-Name Accounting Standards Codification
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-SubTopic 10
-Section S99
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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to statutory income tax expense (benefit) outside of the country of domicile.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to income tax contingencies. Includes, but not limited to, domestic tax contingency, foreign tax contingency, state and local tax contingency, and other contingencies.

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