Stockholders' Equity Tax Status of Distributions (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Class of Stock [Line Items]
Document Fiscal Year Focus	2013
Common Stock [Member]
Class of Stock [Line Items]
Tax status of common stock dividends per share declared	$ 0.180000		$ 0.180000		$ 0.180000
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Tax status of preferred stock dividends per share declared	$ 0.968750		$ 1.937500		$ 1.937500
Series B Preferred Stock [Member]
Class of Stock [Line Items]
Tax status of preferred stock dividends per share declared	$ 1.875000		$ 1.875000		$ 1.875000
Ordinary Dividends [Member] | Common Stock [Member]
Class of Stock [Line Items]
Tax status of common stock dividends per share declared	$ 0.170355		$ 0.124724		$ 0.067853
Ordinary Dividends [Member] | Series A Preferred Stock [Member]
Class of Stock [Line Items]
Tax status of preferred stock dividends per share declared	$ 0.966882		$ 1.342220		$ 0.730053
Ordinary Dividends [Member] | Series B Preferred Stock [Member]
Class of Stock [Line Items]
Tax status of preferred stock dividends per share declared	$ 1.774673		$ 1.298222		$ 0.706502
Long Term Capital Gain [Member] | Common Stock [Member]
Class of Stock [Line Items]
Tax status of common stock dividends per share declared	$ 0.009645		$ 0.055276		$ 0.112147
Unrecaptured Section One Thousand Two Hundred Fifty Gain	$ 0.009457	[1]	$ 0.055276	[1]	$ 0.042574	[1]
Cash Liquidation Distributions	$ 0.000000		$ 0.000000		$ 0.000000
Long Term Capital Gain [Member] | Series A Preferred Stock [Member]
Class of Stock [Line Items]
Tax status of preferred stock dividends per share declared	$ 0.001868		$ 0.595280		$ 1.207447
Unrecaptured Section One Thousand Two Hundred Fifty Gain	$ 0.000000	[1]	$ 0.595280	[1]	$ 0.458393	[1]
Cash Liquidation Distributions	25.000000		0.000000		0.000000
Long Term Capital Gain [Member] | Series B Preferred Stock [Member]
Class of Stock [Line Items]
Tax status of preferred stock dividends per share declared	$ 0.100327		$ 0.576078		$ 1.168498
Unrecaptured Section One Thousand Two Hundred Fifty Gain	$ 0.098519	[1]	$ 0.576078	[1]	$ 0.443606	[1]
Cash Liquidation Distributions	$ 0.000000		$ 0.000000		$ 0.000000

[1] (A)Represents a portion of the dividend allocated to long-term capital gain.