Financial Instruments and Fair Value Measurements - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Minimum [Member]	Jul. 31, 2012 Minimum [Member]	Dec. 31, 2011 Minimum [Member]	Jul. 31, 2012 Maximum [Member]	Dec. 31, 2011 Maximum [Member]
CompX held a series of exchange contracts	$ 4,200,000	$ 4,200,000	$ 17,900,000
Exchange rate	0.98	0.98	1.02	1.03		0.99		1.03
Estimated fair value of the contracts asset	182,000	182,000
Estimated fair value of the contracts liability			19,000
Potential additional cash consideration					0		1,500,000
Fair Value Inputs, Discount Rate		4.00%
Operating income	$ 778,000	$ 778,000