Business and geographic segments - Segment Operating Performance (Detail) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Net sales				$ 2,222.5	$ 2,296.4	$ 1,849.7
Cost of sales				1,732.1	1,716.2	1,437.6
Gross margin				490.4	580.2	412.1
Operating income (loss)				239.4	318.6	186.1
Interest income and other				10.4	4.0	4.7
Insurance recoveries	$ 2.7			2.8	0.1	1.6
Gain on land and related sales		$ 10.4	$ 5.6		16.0	0.5
Changes in market value of Valhi common stock held by subsidiaries				(1.6)	3.3	(1.7)
Other components of net periodic pension and OPEB expense				(13.9)	(17.0)	(20.1)
General expenses, net				(36.6)	(34.7)	(34.3)
Interest expense				(27.9)	(32.5)	(36.2)
Income from continuing operations before income taxes				169.9	257.8	100.6
Depreciation and amortization				58.5	59.3	68.5
Capital expenditures				67.6	64.1	65.5
Other Nonoperating Income (Expense)
Segment Reporting Information [Line Items]
Insurance recoveries				0.1
Chemicals
Segment Reporting Information [Line Items]
Net sales				1,930.2	1,939.4	1,638.8
Cost of sales				1,540.2	1,494.5	1,291.0
Gross margin				390.0	444.9	347.8
Operating income (loss)				174.6	200.8	126.5
Insurance recoveries	$ 2.7
Component Products
Segment Reporting Information [Line Items]
Net sales				166.6	140.8	114.5
Cost of sales				117.8	98.1	81.7
Gross margin				48.8	42.7	32.8
Operating income (loss)				25.4	20.5	11.8
Real Estate Management And Development
Segment Reporting Information [Line Items]
Net sales				125.7	216.2	96.4
Cost of sales				74.1	123.6	64.9
Gross margin				51.6	92.6	31.5
Operating income (loss)				$ 39.4	$ 97.3	$ 47.8