Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Mortgage and notes receivable allowance	$ 5	$ 0
Allowance on receivables	566	1,784
Allowance on accrued rental income	3,078	3,086
Accumulated amortization	$ 9,877	$ 8,514
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	15,000,000	15,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	375,000,000	375,000,000
Common stock, shares issued	141,007,725	132,010,104
Common stock, shares issued and outstanding	141,007,725	132,010,104
Series D Preferred Stock
Depositary shares issued	115,000	115,000
Depositary shares outstanding	115,000	115,000
Stated liquidation value per share (in dollars per share)	$ 2,500	$ 2,500
Dividend rate	6.625%	6.625%
Series E Preferred Stock
Depositary shares issued	115,000	115,000
Depositary shares outstanding	115,000	115,000
Stated liquidation value per share (in dollars per share)	$ 2,500	$ 2,500
Dividend rate	5.70%	5.70%