Financial Highlights (Net Asset Based Total Return For A Shareholder Assuming Conversion Of All LTIP Units) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2012		Sep. 30, 2012		Sep. 30, 2012 Long-Term Incentive Plan Units [Member]	Jun. 30, 2012 Long-Term Incentive Plan Units [Member]	Dec. 31, 2011 Long-Term Incentive Plan Units [Member]	Sep. 30, 2011 Long-Term Incentive Plan Units [Member]	Jun. 30, 2011 Long-Term Incentive Plan Units [Member]	Dec. 31, 2010 Long-Term Incentive Plan Units [Member]
Financial Highlights [Line Items]
Total Return before Incentive Fee	4.22%	[1]	16.81%	[1]
Incentive Fee	(1.94%)	[1]	(2.71%)	[1]
Total Return after Incentive Fee	2.28%	[1]	14.10%	[1]
LTIP units outstanding					395,846	390,500	390,500	388,750	385,000	385,000
Percentage of LTIP units outstanding					1.90%

[1] Total return is calculated assuming all LTIP units had been converted into common shares at September 30, 2012. Total return represents all shareholders' equity accounts, excluding Manager shares, outstanding for the entire period. LTIP units outstanding at September 30, 2012 totaled 395,846 and represent 1.90% of total shares and LTIP units outstanding as of that date.