Commitments and Contingencies (Additional Information) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 claims LegalMatter	Dec. 31, 2013 claim claims LegalMatter	Dec. 31, 2012
Commitments and Contingencies Disclosure [Line Items]
Number of pending claims	438	362
Estimated total cleanup costs, accrual	$ 0.4
Percentage of claims dismissed (more than)	60.00%
Number of claims dismissed	104	115
Number of claims settled	13	23
Claims settlements amount	3.2	4.8
Cost Sharing Agreement, expiration date	Jan. 25, 2015
Asbestos Forecast Claim Period	10 years
Asbestos-related liabilities, estimated liability	56.5
Asbestos-related liabilities, estimated insurance recovery	53.0
Environmental remediation expense (income)	0.8	(0.5)	2.7
Minimum [Member]
Commitments and Contingencies Disclosure [Line Items]
Average number of defendants	50
Number of defendants	1
Maximum [Member]
Commitments and Contingencies Disclosure [Line Items]
Average number of defendants	300
Number of defendants	833
Claims that Specify Amount of Damages Sought not Based on Jurisdictional Requirements [Member] | Legal Claim 1 [Member]
Commitments and Contingencies Disclosure [Line Items]
Number of pending claims	1
Claims that Specify Amount of Damages Sought not Based on Jurisdictional Requirements [Member] | Legal Claim 1 [Member] | Punitive [Member]
Commitments and Contingencies Disclosure [Line Items]
Damages sought	20
Superfund Sites Proceedings [Member]
Commitments and Contingencies Disclosure [Line Items]
Number of pending claims	1
Estimated total cleanup costs, cost sharing percentage	2.00%
Loss contingency, minimum possible loss	18.8
Loss contingency, maximum possible loss	29.6
PCB Contamination Proceedings [Member]
Commitments and Contingencies Disclosure [Line Items]
PCB contamination of the building, liability recording during the period	0.2	0.7
Remediation and monitoring costs incurred since inception related to the PCB soil and building contamination	2.4
PCB Contamination Proceedings [Member] | Building [Member]
Commitments and Contingencies Disclosure [Line Items]
Remediation and monitoring costs incurred since inception related to the PCB soil and building contamination	0.5
Connecticut Voluntary Corrective Action Program (VCAP) [Member]
Commitments and Contingencies Disclosure [Line Items]
Estimated total cleanup costs, accrual	0.1
Claim of Improper Relationship Termination [Member]
Commitments and Contingencies Disclosure [Line Items]
Estimated total cleanup costs, accrual	$ 0.6