Commitments and Contingencies (Details) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) LegalMatter claims	Dec. 31, 2016 claims	Dec. 31, 2015 USD ($)
Loss Contingencies [Line Items]
Environmental remediation expense		$ 0.5
Number of pending claims (legal matter) | claims		663	605
Asbestos forecast claim period		10 years	10 years
Connecticut Voluntary Corrective Action Program
Loss Contingencies [Line Items]
Estimated total cleanup costs, accrual		$ 1.8		$ 3.2
Loss contingency accrual, period decrease	$ 0.9
Superfund Sites Proceedings
Loss Contingencies [Line Items]
Estimated total cleanup costs, accrual		$ 0.4
Number of pending claims (legal matter) | LegalMatter		1
Estimated total cleanup costs, cost sharing percentage (percent)		2.00%
PCB Contamination Proceedings
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies		$ 0.2
Minimum | Superfund Sites Proceedings
Loss Contingencies [Line Items]
Loss contingency, maximum possible loss		18.8
Maximum | Superfund Sites Proceedings
Loss Contingencies [Line Items]
Loss contingency, maximum possible loss		$ 29.6