Commitments and Contingencies (Asbestos Liability) (Detail)	3 Months Ended					6 Months Ended		12 Months Ended
	Jun. 30, 2019 USD ($) Claim	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jun. 30, 2019 USD ($) Claim	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Mar. 31, 2019	Mar. 31, 2018	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]
Payments for asbestos-related fees and costs, net of insurance recoveries						$ 17,900,000	$ 34,900,000
Current portion of total estimated liability	$ 66,000,000.0					$ 66,000,000.0		$ 66,000,000.0
Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Pending claims	28,851	29,920				28,851	29,920	29,089	32,234		28,498	30,990
Payments for asbestos-related fees and costs, net of insurance recoveries	$ 8,200,000	$ 32,000,000.0				$ 17,900,000	$ 34,900,000	$ 63,900,000
Cumulative claims resolved | Claim	138,000					138,000
Settlement cost	$ 630,000,000					$ 630,000,000
Average settlement cost per resolved claim								11,300	$ 7,800	$ 3,900
Cumulative average settlement cost per resolved claim	4,600					4,600
Estimated payments to current and future claimants								36,000,000,000
Additional liability					$ 227,000,000
Liability for claims	491,000,000				$ 696,000,000	491,000,000				$ 696,000,000
Percentage Of Asbestos Liability Attributable To Settlement And Denfese Costs For Future Claims					80.00%					80.00%
Current portion of total estimated liability	$ 66,000,000					$ 66,000,000
Number of buyout agreements with excess insurer groups	10					10
Aggregate value of policy buyout agreements	$ 82,500,000					$ 82,500,000
Estimated Percentage Of Insurance Which Covers Asbestos Costs					21.00%					21.00%
Insurance reimbursement asset	83,000,000				$ 143,000,000	83,000,000				$ 143,000,000
Gross Settlement And Defense Incurred Costs	$ 13,800,000	$ 41,100,000				$ 40,300,000	$ 55,900,000	$ 88,800,000
Mesothelioma Claims Percentage Pending Asbestos Claims					10.00%					10.00%
Mesothelioma Claims Percentage Aggregate Settlement Defense Costs					90.00%					90.00%
Frank Paasch | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Jury Verdict																				$ 2,500,000
PaidJuryVerdict			$ 300,000
Share Of Responsibility Of Verdict																				10.00%
James Nelson | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Jury Verdict																						$ 14,500,000
Share Of Responsibility Of Verdict																						9.09%
Court judgment against all parties held responsible																					$ 4,000,000.0
Additional interest on the compensation awarded																					$ 10,000.00
Larry Bell | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Share Of Responsibility Of Verdict																						5.00%
Frank Vincinguerra | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Jury Verdict																				$ 2,300,000
PaidJuryVerdict					$ 600,000
Share Of Responsibility Of Verdict																				20.00%
Ivo Peraica | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Court Judgment																			$ 10,600,000
Reduced Damages													$ 4,250,000
CourtJudgmentIncludingSetoffs													1,940,000
Paid Judgment Pursuant to Appeal				$ 2,700,000
Jury Verdict Total																			35,000,000
Court_Reduced_Verdict																			$ 18,000,000
Richard DeLisle [Member] | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Court Judgment																		$ 1,300,000
Jury Verdict																		$ 8,000,000
Share Of Responsibility Of Verdict																		16.00%
Ivan Sweberg [Member] | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Court Judgment																	$ 5,300,000
Reduced Damages													9,500,000
CourtJudgmentIncludingSetoffs													4,730,000
Paid Judgment Pursuant to Appeal				$ 5,700,000
Jury Verdict Total																	15,000,000
Court_Reduced_Verdict																	10,000,000
Selwyn Hackshaw [Member] | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Court Judgment																	3,100,000
Reduced Damages													3,000,000
CourtJudgmentIncludingSetoffs													$ 0
Jury Verdict Total																	10,000,000
Court_Reduced_Verdict																	$ 6,000,000
James Poage [Member] | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Compensatory Damages																$ 1,500,000
Additional Damages																10,000,000
Court Judgment																$ 10,800,000
Valent Rabovsky [Member] | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Court Judgment														$ 400,000
Jury Verdict Total															$ 1,085,000.000
Share Of Responsibility Of Verdict															30.00%
George Coulbourn [Member] | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Additional Damages														5,000,000
Court Judgment														6,800,000
Jury Verdict Total														$ 9,000,000
Share Of Responsibility Of Verdict														20.00%
Geoffrey_Anisansel [Member] | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Jury Verdict Total			$ 20,000,000
New York | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Pending claims | Claim	18,000					18,000
Mississippi | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Pending claims | Claim	300					300
Texas | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Pending claims | Claim	100					100
Ohio | Asbestos Commitments and Contingencies
Loss Contingencies [Line Items]
Pending claims | Claim	200					200