Business Combinations, Discontinued Operations and Related Transactions - Summary of Operations of Disposed Furniture Components Business (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2011
Business Combinations Discontinued Operations And Related Transactions [Line Items]
Gain on sale					$ 23.7
Total discontinued operations, net of tax					25.5	4.1
Total discontinued operations, net of tax and noncontrolling interest	16.1	1.2	0.6	0.5	18.4	3.0
Compx Furniture Components
Business Combinations Discontinued Operations And Related Transactions [Line Items]
Net sales					60.7	59.0
Operating income					7.4	9.1
Income before taxes					7.2	9.1
Income tax expense					3.5	5.0
Income from discontinued operations, net of tax					3.7	4.1
Gain on sale					23.7
Income tax expense					1.9
Gain on sale discontinued operations, net of tax					21.8
Total discontinued operations, net of tax					25.5	4.1
Noncontrolling interest in gain on sale of discontinued operations					7.1	1.1
Total discontinued operations, net of tax and noncontrolling interest					18.4	3.0
Compx Furniture Components | Discontinued operations
Business Combinations Discontinued Operations And Related Transactions [Line Items]
Total discontinued operations, net of tax					1.0	1.1
Compx Furniture Components | Gain on sale of discontinued operations
Business Combinations Discontinued Operations And Related Transactions [Line Items]
Noncontrolling interest in gain on sale of discontinued operations					$ 6.1