Summary of Significant Accounting Policies (Details 2) (USD $)	3 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Common Stock, Dividends, Per Share, Declared	$ 0.40	$ 0.40	$ 1.60	$ 1.60	$ 2.04
Ordinary Income [Member]
Common Stock, Dividends, Per Share, Declared			$ 1.20	$ 1.57	$ 1.84
Return Of Capital [Member]
Common Stock, Dividends, Per Share, Declared			$ 0.40	$ 0.03	$ 0.20