Litigation - Summary of Activity in Asbestos Insurance Recoveries (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Loss Contingencies [Line Items]
Insurance receivable – asbestos, beginning of the year		$ 115,945
Insurance receivable – asbestos, end of the period	$ 87,331
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	(13,011)	(12,054)
Insurance receivable – asbestos, end of the period	$ 87,331	$ 103,891