Noncontrolling Interest in Subsidiaries - Noncontrolling Interest in Subsidiaries (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Noncontrolling interest in net assets:
Noncontrolling interest in subsidiaries	$ 369.9	$ 391.5
Basic Management Inc.
Noncontrolling interest in net assets:
Noncontrolling interest in subsidiaries	31.7	33.7
LandWell
Noncontrolling interest in net assets:
Noncontrolling interest in subsidiaries	25.3	27.8
Kronos Worldwide, Inc.
Noncontrolling interest in net assets:
Noncontrolling interest in subsidiaries	241.0	241.9
NL
Noncontrolling interest in net assets:
Noncontrolling interest in subsidiaries	57.8	74.5
CompX
Noncontrolling interest in net assets:
Noncontrolling interest in subsidiaries	$ 14.1	$ 13.6