Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 Claim		Dec. 31, 2013 Claim		Dec. 31, 2012 Claim		Dec. 31, 2011 Claim
Other Commitments [Line Items]
Asbestos-related liability and asset measurement period	10 years
Asbestos Related Matters [Member]
Other Commitments [Line Items]
Outstanding Active Pending Asbestos Claims	62,000		79,000		96,000		105,000
Inactive Asbestos Claim Dismissals	19,000	[1]	19,000	[1]	12,000	[1]
Recorded asbestos liability related to pending claims	30.00%
Percentage of Insurers with A- or Better Credit Ratings	84.00%
Percentage of Asbestos Asset Related to Coverage in Place Agreements	55.00%
Benefit from Settlement Agreement, Continuing Operations	$ 0		$ 31.0		$ 5.8
Benefit from Settlement Agreement, Discontinued Operations					$ 5.6

[1] (a)Dismissals reported in the table above include the dismissal of approximately 16 thousand claims in 2013 and 12 thousand in 2012, which were considered pending inactive claims. There were no inactive claims dismissed during 2014. Inactive claims represent pending claims in Mississippi filed in 2004 or prior, which have been excluded from our asbestos measurement because the plaintiffs cannot demonstrate a significant compensable loss. As such, management believes these claims have little to no value.