Investments - Debt, Equity and Other Securities - Summary of the Company's Portfolio of Cost Method Investments (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Cost-method Investments [Line Items]
Cost of investments	$ 32,681	$ 33,524
Venture capital funds [Member]
Schedule of Cost-method Investments [Line Items]
Cost of investments		64
Equity investments [Member]
Schedule of Cost-method Investments [Line Items]
Cost of investments	32,516	33,298
Convertible note [Member]
Schedule of Cost-method Investments [Line Items]
Cost of investments	$ 165	$ 162