Business Segment Information - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Jun. 30, 2015	Sep. 30, 2015
Chemicals | Employee Severance
Segment Reporting Information [Line Items]
Restructuring charges	$ 21.1	$ 21.5
Kronos Worldwide, Inc.
Segment Reporting Information [Line Items]
Direct controlling interest in subsidiary		50.00%
Indirect controlling interest in subsidiary		30.00%
NL
Segment Reporting Information [Line Items]
Total controlling interest		83.00%
LandWell
Segment Reporting Information [Line Items]
Direct controlling interest in subsidiary		27.00%
Indirect controlling interest in subsidiary		50.00%
BMI
Segment Reporting Information [Line Items]
Total controlling interest		63.00%