Commitments and Contingencies (Additional Information) (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) claims legal_matter	Dec. 31, 2015 USD ($) claims	Dec. 31, 2014 USD ($) claims
Loss Contingencies [Line Items]
Estimated total cleanup costs, accrual	$ 0.4
Number of pending claims | claims	605	489	440
Number of claims dismissed | claims	155	176
Number of claims settled | claims	17	6
Claims settlements amount	$ 4.4	$ 1.6
Asbestos forecast claim period	10 years
Asbestos-related liabilities, estimated liability	$ 52.0	56.6
Asbestos-related liabilities, estimated insurance recovery	48.4	53.4
Environmental remediation expense (income)	0.3	(0.3)	$ 0.8
Connecticut Voluntary Corrective Action Program (VCAP)
Loss Contingencies [Line Items]
Estimated total cleanup costs, accrual	1.9	$ 3.2
Decrease in loss contingency accrual	$ 0.9
Superfund Sites Proceedings
Loss Contingencies [Line Items]
Number of pending claims | legal_matter	1
Estimated total cleanup costs, cost sharing percentage	2.00%
Superfund Sites Proceedings | Minimum
Loss Contingencies [Line Items]
Loss contingency, not accrued, best estimate	$ 18.8
Superfund Sites Proceedings | Maximum
Loss Contingencies [Line Items]
Loss contingency, not accrued, best estimate	29.6
PCB Contamination Proceedings
Loss Contingencies [Line Items]
PCB contamination of the building and pond, liability recording during the period	0.7
Remediation and monitoring costs incurred since inception related to the PCB soil and building contamination	2.3
PCB Contamination Proceedings | Building
Loss Contingencies [Line Items]
Remediation and monitoring costs incurred since inception related to the PCB soil and building contamination			$ 0.5
PCB Contamination Proceedings | Pond
Loss Contingencies [Line Items]
Estimated total cleanup costs, accrual	$ 0.2