Accumulated Other Comprehensive (Loss) Income Narrative (Details)	3 Months Ended
Oct. 31, 2017 USD ($)
Accumulated Other Comprehensive Income
Tax for reclassification adjustment from AOCI for pension and other postretirement benefits	$ 110,000

Amount of tax (expense) benefit of reclassification adjustment from accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.

No definition available.

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