Distributions (Details Textual) (USD $)	0 Months Ended	12 Months Ended		1 Months Ended	12 Months Ended
	Jan. 16, 2013	Dec. 31, 2012	Dec. 31, 2011	May 31, 2011 8.25% Series A Cumulative Redeemable Preferred Stock [Member]	Dec. 31, 2012 8.25% Series A Cumulative Redeemable Preferred Stock [Member]	Dec. 31, 2011 8.25% Series A Cumulative Redeemable Preferred Stock [Member]	Oct. 31, 2012 8.25% Series A Cumulative Redeemable Preferred Stock [Member]	Apr. 10, 2012 8.25% Series A Cumulative Redeemable Preferred Stock [Member]
Distributions (Textual)
Declaration Date	Jan. 16, 2013				Jan. 16, 2013	Jan. 18, 2012
Record Date	Feb. 15, 2013					Feb. 15, 2012
Payment Date	Mar. 15, 2013				Mar. 15, 2013	Mar. 15, 2012
Dividends declared per share	$ 0.18
Preferred stock, dividend declared per share, paid		$ 2.0625	$ 1.065625		$ 0.515625
Cumulative redeemable preferred stock, dividend rate, percentage				8.25%	8.25%
Annual rate on dividend per share payable quarterly					$ 2.0625		$ 0.344	$ 0.292