Commitments and Contingencies - Lead Pigment Litigation and Environmental Matters and Litigation - Additional Information (Detail) $ in Millions	1 Months Ended			3 Months Ended	12 Months Ended
	Sep. 30, 2018 USD ($)	Aug. 31, 2018 USD ($)	May 31, 2018 USD ($) Installment	Jun. 30, 2018 USD ($) Installment	Dec. 31, 2018 USD ($) Cases Installment site	Nov. 30, 2018 Complaint	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Commitments And Contingent Liabilities [Line Items]
Recalculated abatement fund amount undetermined		$ 409.0
Litigation settlement net present value					$ 17.0
Current insurance recovery receivable					15.0
Accrued litigation settlement					60.0
Accrual for reasonably estimable environmental remediation and related matters					103.4		$ 117.5	$ 122.6	$ 120.4
Other Environmental Cleanup Matters
Commitments And Contingent Liabilities [Line Items]
Accrual for reasonably estimable environmental remediation and related matters					5.4
NL
Commitments And Contingent Liabilities [Line Items]
Recalculated abatement fund amount		409.0
Settlement of recalculated abatement fund amount	$ 409.0	409.0
Number of complaints filed | Complaint						2
NL | Environmental Remediation Sites NL Named As PRP Or Defendant
Commitments And Contingent Liabilities [Line Items]
Accrual for reasonably estimable environmental remediation and related matters					$ 98.0
Number of sites associated with remediation and related costs | site					35
Number of sites for which NL not currently able to reasonably estimate range of costs | site					5
NL | Maximum | Environmental Remediation Sites NL Named As PRP Or Defendant
Commitments And Contingent Liabilities [Line Items]
Upper end range, estimate costs for remediation and related matters					$ 117.0
Lead Pigment Litigation
Commitments And Contingent Liabilities [Line Items]
Number of cases settled and dismissed and found not liable | Cases					100
Period by which loss contingency claims settled and dismissed					20 years
Settlement agreement amount			$ 80.0	$ 45.0
Settlement agreement amount to be paid			65.0	62.0
Litigation settlement charge upon trial court's approval			$ 45.0	$ 45.0
Number of annual installments | Installment			5	5	5
Litigation settlement installments payment beginning term from approval			4 years	4 years
Remaining litigation settlement charge			$ 20.0	$ 20.0	$ 20.0
Remaining litigation settlement charge due in first installment			6.0
Remaining litigation settlement charge due in second installment			5.0
Remaining litigation settlement charge due in third installment			3.0
Remaining litigation settlement charge due in fourth installment			3.0
Remaining litigation settlement charge due in fifth installment			3.0
Discounted rate for estimated present value of remaining litigation amount					3.00%
Litigation settlement net present value				17.0	$ 17.0
Current insurance recovery receivable				15.0
Accrued litigation settlement				$ 60.0
Lead Pigment Litigation | Former Insurance Carriers
Commitments And Contingent Liabilities [Line Items]
Settlement agreement amount to be paid			$ 15.0
California Lead Paint Litigation
Commitments And Contingent Liabilities [Line Items]
Amount awarded to the plaintiff					$ 1,150.0
Lead Pigment Litigation Plaintiffs
Commitments And Contingent Liabilities [Line Items]
Proposed abatement fund amount		$ 730.0