Financial Highlights (Results Of Operations For A Share Outstanding) (Details) - $ / shares		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013
Increase (Decrease) Equity Per Share [Roll Forward]
Beginning Shareholders' Equity Per Share (12/31/2015, 12/31/2014, and 12/31/2013, respectively)		$ 22.10	[1]	$ 23.38	[1]	$ 24.40
Net Investment Income		1.09		1.98		2.10
Net Realized/Unrealized Gains (Losses)		(1.57)		(0.83)		0.04
Results of Operations Attributable to Equity		(0.48)		1.15		2.14
Less: Results of Operations Attributable to Non-controlling Interests		(0.01)		(0.01)		(0.03)
Results of Operations Attributable to Shareholders' Equity	[2]	(0.49)		1.14		2.11
Dividends Paid to Common Shareholders		(1.95)		(2.45)		(3.08)
Weighted Average Share Impact on Dividends Paid	[3]	(0.04)		(0.05)		(0.01)
Accretive (Dilutive) Effect of Share Issuances (Net of Offering Costs), Share Repurchases, and Adjustments to Non-controlling Interest		0.13		0.08		(0.04)
Ending Shareholders' Equity Per Share (12/31/2016, 12/31/2015, and 12/31/2014, respectively)(3)	[1]	$ 19.75		$ 22.10		$ 23.38
Shares Outstanding, end of period		32,294,703		33,126,012		33,449,678	25,428,186
Shareholders Equity Per Share Upon Conversion Of All Convertible Units (in usd per share)		$ 19.46		$ 21.80		$ 23.09

[1] If all LTIP Units and OP Units previously issued were vested and exchanged for common shares as of December 31, 2016, 2015, and 2014, shareholders' equity per share would be $19.46, $21.80, and $23.09, 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.