v2.4.0.6
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.