Financial Highlights (Results Of Operations For A Share Outstanding) (Details) - $ / shares		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014
Increase (Decrease) Equity Per Share [Roll Forward]
Beginning Shareholders' Equity Per Share (12/31/2015 and 12/31/2014, respectively)		$ 22.10	$ 23.38
Net Investment Income		0.36	0.52
Net Realized/Unrealized Gains (Losses)		(1.06)	0.06
Results of Operations Attributable to Equity		(0.70)	0.58
Less: Results of Operations Attributable to Non-controlling Interests		0.00	0.00
Results of Operations Attributable to Shareholders' Equity	[1]	(0.70)	0.58
Dividends Paid to Common Shareholders		(0.50)	(0.65)
Weighted Average Share Impact on Dividends Paid	[2]	(0.01)	(0.01)
Accretive (Dilutive) Effect of Share Issuances (Net of Offering Costs), Share Repurchases, and Adjustments to Non-controlling Interest		0.02	0.00
Ending Shareholders' Equity Per Share (3/31/2016 and 3/31/2015, respectively)(3)	[3]	$ 20.91	$ 23.30
Shares Outstanding, end of period		32,962,979	33,449,678	33,126,012	33,449,678
Shareholders Equity Per Share Upon Conversion Of All Convertible Units (in usd per share)		$ 20.63	$ 23.01

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

[2] 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.

[3] If all LTIP units and OP Units previously issued were vested and exchanged for common shares as of March 31, 2016 and 2015, shareholders' equity per share would be $20.63 and $23.01, respectively.