Financial Instruments - Summary of Financial Instruments Not Carried at Fair Value (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Noncontrolling interest in subsidiary	$ 16,350	$ 15,301
Carrying Amount
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash, cash equivalents and restricted cash	98,242	100,981
Carrying Amount | CompX
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Noncontrolling interest in subsidiary	16,350	15,301
Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash, cash equivalents and restricted cash	98,242	100,981
Fair Value | CompX
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Noncontrolling interest in subsidiary	$ 26,790	$ 18,878