Financial Highlights (Results Of Operations For A Share Outstanding) (Details) - $ / shares		12 Months Ended
		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012
Increase (Decrease) Equity Per Share [Roll Forward]
Beginning Shareholders' Equity Per Share (12/31/2014, 12/31/2013, and 12/31/2012, respectively)		$ 23.38	[1]	$ 24.40	[1]	$ 24.86
Net Investment Income		1.98		2.10		2.11
Net Realized/Unrealized Gains (Losses)		(0.83)		0.04		1.26
Results of Operations Attributable to Equity		1.15		2.14		3.37
Less: Results of Operations Attributable to Non-controlling Interests		(0.01)		(0.03)		(0.04)
Results of Operations Attributable to Shareholders' Equity	[2]	1.14		2.11		3.33
Dividends Paid to Common Shareholders		(2.45)		(3.08)		(3.83)
Weighted Average Share Impact on Dividends Paid	[3]	(0.05)		(0.01)		(0.08)
Accretive (Dilutive) Effect of Share Issuances (Net of Offering Costs), Share Repurchases, and Adjustments to Non-controlling Interest		0.08		(0.04)		0.12
Ending Shareholders' Equity Per Share (12/31/2015, 12/31/2014, and 12/31/2013, respectively)(3)	[1]	$ 22.10		$ 23.38		$ 24.40
Shares Outstanding, end of period		33,126,012		33,449,678		25,428,186	20,370,469
Shareholders Equity Per Share Upon Conversion Of All Convertible Units (in usd per share)		$ 21.80		$ 23.09		$ 23.99

[1] If all LTIP units and OP Units previously issued were vested and exchanged for common shares as of December 31, 2015, 2014, and 2013, shareholders' equity per share would be $21.80, $23.09, and $23.99, respectively.

[2] Calculated based on average common shares outstanding and can differ from the calculation for EPS (See Note 11).

[3] Per share impact on dividends paid relating to share issuances/repurchases during the period as well as dividends paid to LTIP and OP Unit holders.