Litigation - Summary of Activity in Asbestos Insurance Recoveries (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Loss Contingencies [Line Items]
Insurance receivable – asbestos, beginning of the year		$ 115,945
Insurance receivable – asbestos, end of the period	$ 95,388
Asbestos Claims [Member]
Loss Contingencies [Line Items]
Insurance receivable – asbestos, beginning of the year	100,342	115,945
Settlement and defense costs paid by insurance carriers	(4,954)	(3,626)
Insurance receivable – asbestos, end of the period	$ 95,388	$ 112,319