Commitments and Contingencies (Schedule Of Activity Related To Asbestos Claim) (Detail)	3 Months Ended		12 Months Ended
	Mar. 31, 2020 USD ($) claim	Mar. 31, 2019 USD ($) claim	Dec. 31, 2019 USD ($) claim	Dec. 31, 2018 USD ($) claim	Dec. 31, 2017 USD ($)	Apr. 22, 2016 USD ($)	Jul. 02, 2015 USD ($)	Sep. 17, 2013 USD ($)	Feb. 25, 2013	Feb. 23, 2011 USD ($)	Mar. 23, 2010 USD ($)
Loss Contingencies [Line Items]
Current asbestos liability	$ 65,000,000.0		$ 65,000,000.0
Payments for asbestos-related fees and costs, net of insurance recoveries	11,700,000	$ 9,700,000
Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Asbestos Settlement Cost Per Resolved Claim			15,800	$ 11,300	$ 7,800
Current asbestos liability			$ 65,000,000
Aggregate Value Of Policy Buy Out Agreements	82,500,000
Court Judgment	$ 12,600,000	$ 26,500,000
Beginning claims | claim	29,056	29,089	29,089
New claims | claim	681	675	2,848
Settlements | claim	165	408	983
Dismissals | claim	410	858	1,898
Ending claims | claim	29,162	28,498	29,056	29,089
Gross Settlement And Defense Incurred Costs	$ 12,600,000	$ 26,500,000	$ 66,200,000
Payments for asbestos-related fees and costs, net of insurance recoveries	$ 11,700,000	$ 9,700,000	$ 41,500,000
New York | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Ending claims | claim	18,000
Texas | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Ending claims | claim	100
Mississippi | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Ending claims | claim	300
OHIO | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Ending claims | claim	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]
Share Of Responsibility Of Verdict									10.00%
Frank Vincinguerra | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Share Of Responsibility Of Verdict									20.00%
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%
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
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