Financial Highlights (Results Of Operations For A Share Outstanding) (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011		Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011	Dec. 31, 2010
Financial Highlights [Abstract]
Beginning Shareholders' Equity Per Share	$ 24.03		$ 23.31		$ 22.55		$ 24.47
Net Investment Income	$ 0.04		$ 0.67		$ 1.21		$ 2.04
Net Realized/Unrealized Gains (Losses)	$ 1.59		$ (0.74)		$ 3.04		$ (1.52)
Results of Operations	$ 1.63	[1]	$ (0.07)	[1]	$ 4.25	[1]	$ 0.52	[1]
Dividends Paid	$ (0.70)		$ (0.40)		$ (1.80)		$ (2.11)
Weighted Average Share Impact on Dividends Paid	$ (0.08)	[2]	$ (0.01)	[2]	$ (0.12)	[2]	$ (0.05)	[2]
Accretive (Dilutive) Effect of Share Issuances (Net of Offering Costs) and Share Repurchases	$ (0.54)		$ 0.01		$ (0.54)		$ 0.01
Ending Shareholders' Equity Per Share	$ 24.34	[3]	$ 22.84	[3]	$ 24.34	[3]	$ 22.84	[3]
Shares Outstanding, end of period	20,483,696		16,489,881		20,483,696		16,489,881		16,447,651	16,447,651	16,507,381	16,498,342
Shareholders' equity per share upon conversion	$ 23.88		$ 22.32		$ 23.88		$ 22.32			$ 22.03

[1] Calculated based on average common shares outstanding and can differ from the calculation for EPS (See Note 8).

[2] Per share impact on dividends paid relating to share issuances/repurchases during the period as well as dividends paid to LTIP unit holders.

[3] If all LTIP units previously issued were vested and exchanged for common shares as of September 30, 2012 and 2011, shareholders' equity per share would be $23.88 and $22.32, respectively.