Litigation - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Reserves for total costs for asbestos liability claims pending or projected	$ 171,181	$ 131,220
Percentage attributable to settlement costs for unasserted claims projected to be filed	70.00%
Insurance recoveries receivable	$ 115,945	$ 87,331

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14435-108349

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14557-108349

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=115931803&loc=d3e12021-110248

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant