Commitments and Contingent Liabilities (Details) $ in Millions	9 Months Ended
	Jul. 31, 2016 USD ($) regulatory_commission
Site Contingency [Line Items]
Accrual For Environmental Loss Contingencies Gross	$ 1.0
Long-term Purchase Commitment [Line Items]
Number Of Regulatory Commissions | regulatory_commission	3
Letter Of Credit
Guarantor Obligations [Line Items]
Total contingent obligation	$ 1.7
Surety Bond
Guarantor Obligations [Line Items]
Total contingent obligation	6.5
Manufactured Gas Plant Sites
Site Contingency [Line Items]
Accrual For Environmental Loss Contingencies Gross	0.9
Other Environmental Remediation Sites
Site Contingency [Line Items]
Accrual For Environmental Loss Contingencies Gross	$ 0.1
Pipeline And Storage Capacity Contacts | Maximum
Long-term Purchase Commitment [Line Items]
Long term purchase commitment time period	20 years
Reservation Fees Under Gas Supply Contracts | Maximum
Long-term Purchase Commitment [Line Items]
Long term purchase commitment time period	1 year
Gas Supply Purchase Commitments | Maximum
Long-term Purchase Commitment [Line Items]
Long term purchase commitment time period	15 years
Telecommunications And Technology Outsourcing Contracts | Maximum
Long-term Purchase Commitment [Line Items]
Long term purchase commitment time period	5 years