Defined Contribution Plans (Details) - USD ($) $ in Millions	12 Months Ended
Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
Defined Contribution Plans [Abstract]
Total plan expense	$ 1.3	$ 1.5	$ 1.4

Amount of administrative expense incurred by defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanAdministrativeExpenses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration