Commitments and Contingencies (Schedule Of Activity Related To Asbestos Claim) (Detail)	3 Months Ended					9 Months Ended		12 Months Ended
	Sep. 30, 2019 USD ($) claim agreement	Sep. 30, 2018 USD ($) claim	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2019 USD ($) claim agreement	Sep. 30, 2018 USD ($) claim	Dec. 31, 2018 USD ($) claim	Dec. 31, 2017 USD ($) claim	Dec. 31, 2016 USD ($)	Oct. 06, 2016 USD ($)	Apr. 22, 2016 USD ($)	Feb. 09, 2016 USD ($)	Jul. 02, 2015 USD ($)	Jun. 16, 2014 USD ($)	Sep. 17, 2013 USD ($)	Mar. 01, 2013 USD ($)	Feb. 25, 2013 USD ($)	Feb. 23, 2011 USD ($)	Mar. 23, 2010 USD ($)
Loss Contingencies [Line Items]
Current asbestos liability	$ 66,000,000.0					$ 66,000,000.0		$ 66,000,000.0
Payments for asbestos-related fees and costs, net of insurance recoveries						29,000,000.0	$ 46,400,000
Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Asbestos Settlement Cost Per Resolved Claim								$ 11,300	$ 7,800	$ 3,900
Current asbestos liability	$ 66,000,000					$ 66,000,000
Number of buyout agreements with excess insurer groups | agreement	10					10
Aggregate Value Of Policy Buy Out Agreements	$ 82,500,000					$ 82,500,000
Beginning claims | claim		29,323				29,089	32,234	32,234
New claims | claim	746	574				2,190	1,802	2,434
Settlements | claim	(177)	(174)				(763)	(779)	(1,011)
Dismissals | claim	(591)	(997)				(1,687)	(3,934)	(4,568)
Ending claims | claim	28,829					28,829		29,089	32,234
Gross Settlement And Defense Incurred Costs	$ 13,900,000	$ 13,800,000				$ 54,200,000	$ 69,700,000	$ 88,800,000
Payments for asbestos-related fees and costs, net of insurance recoveries	$ 11,000,000.0	$ 11,600,000				$ 28,900,000	$ 46,400,000	$ 63,900,000
New York | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Ending claims | claim	18,000					18,000
Texas | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Ending claims | claim	100					100
Mississippi | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Ending claims | claim	300					300
OHIO | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Ending claims | claim	200					200
James Nelson | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Jury Verdict																				$ 14,500,000
Court Judgment Against All Parties Held Responsible																			$ 4,000,000.0
Additional Judgment Interest																			$ 10,000.00
Share Of Responsibility Of Verdict																				9.09%
Thomas Amato | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Jury Verdict																		$ 2,500,000
Share Of Responsibility Of Verdict																		10.00%
PaidJuryVerdict			$ 300,000
Frank Vincinguerra | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Jury Verdict																		$ 2,300,000
Share Of Responsibility Of Verdict																		20.00%
PaidJuryVerdict					$ 600,000
Ivo Peraica | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Court Judgment																	$ 10,600,000
Court_Reduced_Verdict																	18,000,000
Paid Judgment Pursuant to Appeal				$ 2,700,000
Jury Verdict Total																	$ 35,000,000
Reduced Damages											$ 4,250,000
CourtJudgmentIncludingSetoffs											1,940,000
Richard DeLisle | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Jury Verdict																$ 8,000,000
Court Judgment																$ 1,300,000
Share Of Responsibility Of Verdict																16.00%
Ivan Sweberg | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Court Judgment															$ 5,300,000
Court_Reduced_Verdict															10,000,000
Paid Judgment Pursuant to Appeal				$ 5,700,000
Jury Verdict Total															15,000,000
Reduced Damages											9,500,000
CourtJudgmentIncludingSetoffs											4,730,000
Selwyn Hackshaw | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Court Judgment															3,100,000
Court_Reduced_Verdict															6,000,000
Jury Verdict Total															$ 10,000,000
Reduced Damages											3,000,000
CourtJudgmentIncludingSetoffs											$ 0
James Poage | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Court Judgment														$ 10,800,000
compensatory_damages														1,500,000
Additional Damages														$ 10,000,000
Valent Rabovsky | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Court Judgment												$ 400,000
Share Of Responsibility Of Verdict													30.00%
Jury Verdict Total													$ 1,085,000.000
George Coulbourn | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Court Judgment												$ 6,800,000
Share Of Responsibility Of Verdict												20.00%
Jury Verdict Total												$ 9,000,000
Additional Damages												$ 5,000,000
Geoffrey_Anisansel | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Jury Verdict Total			$ 20,000,000