Stockholders' Equity - Summary of Preferred Shares Outstanding (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013
Series F Preferred Stock
Class of Stock [Line Items]
Preferred Shares Outstanding	500
Liquidation Preference	$ 50,000
Series G Preferred Stock
Class of Stock [Line Items]
Preferred Shares Outstanding	250
Liquidation Preference	$ 25,000