Distributions (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Common Share Distributions:
Ordinary income	$ 0.37	$ 0.60	$ 0.60
Capital gain	$ 0.0	$ 0.0	$ 0.0
Non-taxable distributions	$ 0.23	$ 0.0	$ 0.0
Distributions per share	$ 0.60	$ 0.60	$ 0.60
Percentage classified as ordinary income (as a percent)	61.67%	100.00%	100.00%
Percentage classified as capital gain (as a percent)	0.00%	0.00%	0.00%
Percentage classified as non-taxable distribution (as a percent)	38.33%	0.00%	0.00%
Preferred Share Distributions:
Total distributions declared (in dollars)	$ 7,992	$ 7,992	$ 7,992