Other Data (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Characterization of distributions on common stock
Ordinary income per share	$ 0.50	$ 0.27	$ 0.63
Return of capital per share	$ 0.70	$ 0.80	$ 0.56
Unrecaptured section 1250 gain per share	$ 0.00	$ 0.13	$ 0.01
Common stock distributions per share	$ 1.2	$ 1.2	$ 1.2
Ordinary income in percent of common stock distribution	42.00%	22.20%	52.30%
Return of capital in percent of common stock distribution	58.00%	66.30%	47.10%
Unrecaptured section 1250 gain in percent of common stock distribution	0.00%	11.50%	0.60%
Common stock distribution in percentage	100.00%	100.00%	100.00%