Commitments and Contingencies - Activity Related to Asbestos Claims (Detail) (Asbestos Related Matters [Member])	12 Months Ended
	Dec. 31, 2014 Claim		Dec. 31, 2013 Claim		Dec. 31, 2012 Claim
Number of Pending Claims [Roll Forward]
Pending claims - Beginning	79,000		96,000		105,000
New claims	4,000		5,000		4,000
Settlements	(2,000)		(3,000)		(1,000)
Dismissals	(19,000)	[1]	(19,000)	[1]	(12,000)	[1]
Pending claims - Ending	62,000		79,000		96,000
Inactive [Member]
Number of Pending Claims [Roll Forward]
Pending claims - Beginning	13,000		29,000
Dismissals	0		(16,000)		(12,000)
Pending claims - Ending	13,000		13,000		29,000
Active [Member]
Number of Pending Claims [Roll Forward]
Pending claims - Ending	49,000		66,000		67,000

[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.