Federal Income Taxes (Details 2) (USD $)	3 Months Ended												12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 30, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Characterization of distributions paid per common share
Amount of distributions paid per common share	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.72	$ 0.72	$ 0.72
Percentage of distributions paid per common share													100.00%	100.00%	100.00%
Ordinary Income [Member]
Characterization of distributions paid per common share
Amount of distributions paid per common share													$ 0.01114	$ 0.12844	$ 0.07892
Percentage of distributions paid per common share													1.55%	17.84%	10.96%
Capital Gains [Member]
Characterization of distributions paid per common share
Amount of distributions paid per common share													$ 0.00265	$ 0.05835	$ 0.08391
Percentage of distributions paid per common share													0.37%	8.10%	11.65%
Return of Capital [Member]
Characterization of distributions paid per common share
Amount of distributions paid per common share													$ 0.70621	$ 0.53321	$ 0.55717
Percentage of distributions paid per common share													98.08%	74.06%	77.39%