Financial Highlights (Results Of Operations For A Share Outstanding) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014	Dec. 31, 2013
Increase (Decrease) Equity Per Share [Roll Forward]
Beginning Shareholders' Equity Per Share (12/31/2014 and 12/31/2013, respectively)	$ 23.38		$ 24.40
Net Investment Income	$ 0.52		$ 0.55
Net Realized/Unrealized Gains (Losses)	$ 0.06		$ 0.35
Results of Operations Attributable to Equity	$ 0.58		$ 0.90
Less: Results of Operations Attributable to Non-controlling Interests	$ 0.00		$ (0.01)
Results of Operations Attributable to Shareholders' Equity	$ 0.58	[1]	$ 0.89	[1]
Dividends Paid Per Common Share	$ (0.65)		$ (0.77)
Weighted Average Share Impact on Dividends Paid (2)	$ (0.01)	[2]	$ (0.02)	[2]
Accretive (Dilutive) Effect of Share Issuances (Net of Offering Costs), Share Repurchases, and Adjustments to Non-controlling Interest	$ 0.00		$ (0.01)
Ending Shareholders' Equity Per Share (3/31/2015 and 3/31/2014, respectively)(3)	$ 23.30	[3]	$ 24.49	[3]
Shares Outstanding, end of period	33,449,678		25,441,750		33,449,678	25,428,186
Shareholders Equity Per Share Upon Conversion Of All Convertible Units (in usd per share)	$ 23.01		$ 24.10

[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, 2015 and 2014, shareholders' equity per share would be $23.01 and $24.10, respectively.