Investments - Debt, Equity and Other Securities - Summary of the Company's Portfolio of Cost Method Investments (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Cost Method Investments [Line Items]
Cost of investments	$ 32,516	$ 33,672
Equity investments [Member]
Schedule Of Cost Method Investments [Line Items]
Cost of investments	$ 32,516	32,516
Convertible notes [Member]
Schedule Of Cost Method Investments [Line Items]
Cost of investments		$ 1,156