Discontinued Operations - Schedule of Condensed Income Statement (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Income from discontinued operations, net of tax	$ 1.8	$ 3.3
Compx Furniture Components
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net sales	15.8	46.4
Operating income	2.7	5.8
Income before taxes	2.7	5.7
Income tax expense	0.9	2.4
Income from discontinued operations, net of tax	1.8	3.3
Noncontrolling interest in income from discontinued operations	0.6	1.0
Compx Furniture Components | Net of Noncontrolling Interest
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Total discontinued operations, net of tax and noncontrolling interest	$ 1.2	$ 2.3