Stockholders' Equity - Dividend Distributions (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Class of Stock [Line Items]
Distributions Per Share	$ 0.085	$ 0	$ 0.17	$ 0
Total Dividend/Distribution			$ 19,286
Total Dividend/Distribution			6,114
Common Stock
Class of Stock [Line Items]
Distributions Per Share			$ 0.17
Total Dividend/Distribution			19,286
Series F Preferred Stock [Member]
Class of Stock [Line Items]
Dividend/Distribution per Share			$ 2,725.32
Total Dividend/Distribution			1,363
Series G Preferred Stock [Member]
Class of Stock [Line Items]
Dividend/Distribution per Share			$ 3,618.00
Total Dividend/Distribution			905
Series J Preferred Stock [Member]
Class of Stock [Line Items]
Dividend/Distribution per Share			$ 5,085.12
Total Dividend/Distribution			2,034
Series K Preferred Stock [Member]
Class of Stock [Line Items]
Dividend/Distribution per Share			$ 9,062.60
Total Dividend/Distribution			$ 1,812