Stockholders' Equity - Summary of Preferred Shares Outstanding (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Class of Stock [Line Items]
Liquidation Preference	$ 75,000
Series F Preferred Stock
Class of Stock [Line Items]
Preferred Shares Outstanding	500	500
Liquidation Preference	50,000	50,000
Series G Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Shares Outstanding	250	250
Liquidation Preference	25,000	25,000
Series J Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Shares Outstanding		400
Liquidation Preference		100,000
Series K Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Shares Outstanding		200
Liquidation Preference		$ 50,000