Distributions (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Dividends, Common Stock [Abstract]
Common Share Distributions Payments of Ordinary Dividends	$ 0.39	$ 0.37	$ 0.60
Common Share Distributions Capital Gain	$ 0.00	$ 0.00	$ 0.00
Common Share Distributions Non-taxable Distributions	$ 0.21	$ 0.23	$ 0.00
Common Stock, Dividends, Per Share, Declared	$ 0.60	$ 0.60	$ 0.60
Percentage Of Distributions classified as ordinary income	65.00%	61.67%	100.00%
Percentage Of Distributions classified as capital gain	0.00%	0.00%	0.00%
Percentage Of Distributions classified as non-taxable distribution	35.00%	38.33%	0.00%
Dividends, Preferred Stock	$ 10,405	$ 7,992	$ 7,992
Percentage Of Preferred Distributions classified as ordinary income	100.00%	100.00%	100.00%