Income taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Dec. 31, 2017	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Line Items]
Dividends received from Kronos Worldwide, Inc.			$ 26,766	$ 25,356	$ 25,356
Gross unrecognized tax benefits			7,300	7,300	7,300
Uncertain tax position			2,714	1,724
Unrecognized tax benefits, if recognize which would affect effective tax rate			7,300
Currently payable			500
Income tax expense (benefit)			(2,785)	(7,479)	2,515
Current payable to affiliate			665	691
Valhi | Income Tax Payable
Income Tax Disclosure [Line Items]
Payable to affiliate			44,700
Federal Income Tax Purposes
Income Tax Disclosure [Line Items]
Net operating loss carryforwards			$ 21,900
Annual usage limitation			80.00%
Net operating loss carryforwards expiration description			an indefinite carryforward period subject to an 80% annual usage limitation
Kronos
Income Tax Disclosure [Line Items]
Dividends received from Kronos Worldwide, Inc.			$ 26,800	$ 25,400	$ 25,400
Non-cash income tax benefit			3,500
Kronos | CARES Act
Income Tax Disclosure [Line Items]
Cash tax benefit due to reversal of valuation allowance	$ 500
Percentage of adjusted taxable income				50.00%	30.00%
Interest expense and an increase in the valuation allowance			2,800
Kronos | Deferred Tax Liability Non Current
Income Tax Disclosure [Line Items]
Uncertain tax position			4,600
Kronos | Corporate Tax Purposes | German
Income Tax Disclosure [Line Items]
Net operating loss carryforwards			414,000
Kronos | Corporate Tax Purposes | Belgium
Income Tax Disclosure [Line Items]
Net operating loss carryforwards			$ 13,000
Kronos European Subsidiaries | Transition Tax
Income Tax Disclosure [Line Items]
Currently payable		$ 74,500
Current income tax expense payment period		8 years
Kronos European Subsidiaries | Valhi
Income Tax Disclosure [Line Items]
Income tax liability payable period			8 years
Kronos European Subsidiaries | Valhi | Income Tax Payable
Income Tax Disclosure [Line Items]
Payable to affiliate			$ 44,700
Noncurrent payable to affiliate			33,500
Current payable to affiliate			$ 11,200