Commitments and contingencies - Additional Information (Detail) $ in Thousands		1 Months Ended					12 Months Ended
	Jul. 24, 2019 USD ($) defendant installment	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2023 USD ($) site case	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Commitments and Contingent Liabilities [Line Items]
Recognized accretion expense							$ 695	$ 908	$ 1,116
Accrual for reasonably estimable environmental remediation and related matters							$ 91,106	$ 92,358	$ 92,940	$ 93,416
Component Products | Customer Concentration Risk | Top Ten Customers | Sales Revenue
Commitments and Contingent Liabilities [Line Items]
Concentration risk percentage							52.00%	52.00%	51.00%
Component Products | Customer Concentration Risk | Customer Two | Sales Revenue | CompX Security Products Business
Commitments and Contingent Liabilities [Line Items]
Concentration risk percentage							24.00%	14.00%	16.00%
Component Products | Customer Concentration Risk | Customer Two | Sales Revenue | CompX Security Products Business | Pilot project
Commitments and Contingent Liabilities [Line Items]
Concentration risk percentage							11.00%
Component Products | Customer Concentration Risk | One customer | Sales Revenue | CompX Security Products Business
Commitments and Contingent Liabilities [Line Items]
Concentration risk percentage								12.00%
Environmental Remediation Sites NL Named As PRP Or Defendant
Commitments and Contingent Liabilities [Line Items]
Accrual for reasonably estimable environmental remediation and related matters							$ 91,000
Number of sites associated with remediation and related costs | site							33
Number of sites currently not able to reasonably estimate a range of costs | site							5
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							$ 118,000
Environmental Remediation Litigation
Commitments and Contingent Liabilities [Line Items]
Recoveries receivable							$ 0	$ 0
Lead Pigment Litigation
Commitments and Contingent Liabilities [Line Items]
Period by which loss contingency claims settled and dismissed							30 years
Description of defendants							on July 24, 2019, an order approving a global settlement agreement entered into among all of the plaintiffs and the three defendants remaining in the case (the Sherwin Williams Company, ConAgra Grocery Products and us) was entered by the court and the case was dismissed with prejudice. The global settlement agreement provides that an aggregate $305 million will be paid collectively by the three co-defendants in full satisfaction of all claims resulting in a dismissal of the case with prejudice and the resolution of (i) all pending and future claims by the plaintiffs in the case, and (ii) all potential claims for contribution or indemnity between us and our co-defendants in respect to the case
Number of defendants | defendant	3
Litigation settlement amount	$ 305,000
NL's portion of global settlement amount, gross value	101,700
Litigation initial payment made 60 days after litigation settlement	25,000
Remaining litigation settlement charge	$ 76,700
Recognized accretion expense							$ 700	$ 900	$ 1,100
Number of annual installments | installment	6
Remaining litigation settlement payment due in first year	$ 12,000
Remaining litigation settlement payment due in second year	12,000
Remaining litigation settlement payment due in third year	12,000
Remaining litigation settlement payment due in forth year	12,000
Remaining litigation settlement payment due in fifth year	12,000
Remaining litigation settlement payment due in sixth year	16,700
Escrow deposit	$ 9,000
Litigation initial payment		$ 12,000	$ 12,000	$ 12,000	$ 12,000	$ 25,000
Discounted rate for estimated present value of remaining litigation amount										1.90%
Litigation settlement estimated net present value										$ 96,300
Insurance recoveries							$ 500
Lead Pigment Litigation | Minimum
Commitments and Contingent Liabilities [Line Items]
Number of cases settled and dismissed and found not liable | case							100