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Schedule III - Real Estate Owned (UNITED DOMINION REALTY, L.P.) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Real Estate and Accumulated Depreciation [Line Items]            
Deferred Finance Costs, Net         $ 0  
Total Carrying Value $ 8,383,259 $ 8,207,977 $ 8,055,828 $ 9,190,276 8,383,259 $ 8,207,977
Accumulated Depreciation 2,434,772 2,208,794 1,924,682 2,646,874 2,434,772 2,208,794
Aggregate cost for federal income tax purposes       8,300,000    
Real Estate Owned, Gross [Roll Forward]            
Balance at beginning of the year 8,383,259 8,207,977 8,055,828      
Real estate acquired 906,446 231,225 0      
Capital expenditures and development 203,183 326,461 452,057      
Real estate sold (301,920) (269,681) (70,687)      
Real Estate Investment Property, at Cost       9,053,599 8,205,627  
Hurricane related impairment of assets (692) (379) (2,355)      
Balance at end of the year 9,190,276 8,383,259 8,207,977      
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at beginning of the year 2,434,772 2,208,794 1,924,682      
Depreciation expense for the year 364,622 356,673 339,326      
Accumulated depreciation on sales (152,520) (126,151) (34,794)      
Accumulated depreciation on retirements of fully depreciated asset 0 0 (1,132)      
Write off of accumulated depreciation on hurricane related impaired assets 0 (316) 0      
Balance at end of year $ 2,646,874 2,434,772 2,208,794      
Estimated depreciable lives of buildings range beginning            
Real Estate and Accumulated Depreciation [Line Items]            
Depreciable life for all buildings 35 years          
Estimated depreciable lives of buildings range end            
Real Estate and Accumulated Depreciation [Line Items]            
Depreciable life for all buildings 55 years          
Other            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances [1]       0    
Initial Costs, Land and Land Improvements [1]       0    
Initial Costs, Buildings and Improvements [1]       0    
Total Initial Acquisition Costs [1]       0    
Costs of Improvements Capitalized Subsequent to Acquisition Costs [1]       5,356    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements [1]       0    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements [1]       5,356    
Total Carrying Value [1] $ 5,356     5,356    
Accumulated Depreciation [1] 62     62    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year [1] 5,356          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year [1] 62          
TOTAL CORPORATE            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       11,755    
Initial Costs, Land and Land Improvements       3,034    
Initial Costs, Buildings and Improvements       20,534    
Total Initial Acquisition Costs       23,568    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,093    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       3,034    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       26,627    
Total Carrying Value 29,661     29,661    
Accumulated Depreciation 691     691    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 29,661          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 691          
Real Estate Under Development            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       78,085    
Initial Costs, Buildings and Improvements       0    
Total Initial Acquisition Costs       78,085    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       45,987    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       78,085    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       45,987    
Total Carrying Value 124,072     124,072    
Accumulated Depreciation 0     0    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 124,072          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 0          
Land            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       56,782    
Initial Costs, Buildings and Improvements       0    
Total Initial Acquisition Costs       56,782    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       23,838    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       63,923    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       16,697    
Total Carrying Value 80,620     80,620    
Accumulated Depreciation 2,935     2,935    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 80,620          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 2,935          
Commercial Held for Development            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       32,351    
Initial Costs, Buildings and Improvements       0    
Total Initial Acquisition Costs       32,351    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       30,909    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       40,197    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       23,063    
Total Carrying Value 63,260     63,260    
Accumulated Depreciation 16,504     16,504    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 63,260          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 16,504          
Commercial Held for Development | TOTAL COMMERCIAL & CORPORATE            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       11,755    
Initial Costs, Land and Land Improvements       35,385    
Initial Costs, Buildings and Improvements       20,534    
Total Initial Acquisition Costs       55,919    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       37,002    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       43,231    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       49,690    
Total Carrying Value 92,921     92,921    
Accumulated Depreciation 17,195     17,195    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 92,921          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 17,195          
Commercial Held for Development | Total Real Estate Owned            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       1,376,945    
Initial Costs, Land and Land Improvements       1,877,466    
Initial Costs, Buildings and Improvements       4,870,890    
Total Initial Acquisition Costs       6,748,356    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       2,441,920    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       2,095,022    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       7,095,254    
Total Carrying Value 9,190,276     9,190,276    
Accumulated Depreciation 2,646,874     2,646,874    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 9,190,276          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 2,646,874          
Western Region            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       466,881    
Initial Costs, Land and Land Improvements       804,897    
Initial Costs, Buildings and Improvements       1,504,019    
Total Initial Acquisition Costs       2,308,916    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       1,019,059    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       883,471    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       2,444,504    
Total Carrying Value 3,327,975     3,327,975    
Accumulated Depreciation 1,037,095     1,037,095    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 3,327,975          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 1,037,095          
Western Region | Harbor at Mesa Verde            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       61,050    
Initial Costs, Land and Land Improvements       20,476    
Initial Costs, Buildings and Improvements       28,538    
Total Initial Acquisition Costs       49,014    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       14,641    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       21,314    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       42,341    
Total Carrying Value 63,655     63,655    
Accumulated Depreciation 27,697     27,697    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 63,655          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 27,697          
Western Region | 27 Seventy FIve Mesa Verde [Member]            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       36,423    
Initial Costs, Land and Land Improvements       99,329    
Initial Costs, Buildings and Improvements       110,644    
Total Initial Acquisition Costs       209,973    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       92,673    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       112,650    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       189,996    
Total Carrying Value 302,646     302,646    
Accumulated Depreciation 87,007     87,007    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 302,646          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 87,007          
Western Region | Pacific Shores            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       42,552    
Initial Costs, Land and Land Improvements       7,345    
Initial Costs, Buildings and Improvements       22,624    
Total Initial Acquisition Costs       29,969    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       9,913    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       7,913    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       31,969    
Total Carrying Value 39,882     39,882    
Accumulated Depreciation 20,771     20,771    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 39,882          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 20,771          
Western Region | Huntington Vista            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       36,980    
Initial Costs, Land and Land Improvements       8,055    
Initial Costs, Buildings and Improvements       22,486    
Total Initial Acquisition Costs       30,541    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       11,612    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       8,713    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       33,440    
Total Carrying Value 42,153     42,153    
Accumulated Depreciation 19,810     19,810    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 42,153          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 19,810          
Western Region | Missions at Back Bay            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       229    
Initial Costs, Buildings and Improvements       14,129    
Total Initial Acquisition Costs       14,358    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       2,526    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       10,874    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       6,010    
Total Carrying Value 16,884     16,884    
Accumulated Depreciation 4,229     4,229    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 16,884          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 4,229          
Western Region | Coronado at Newport — North            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       62,516    
Initial Costs, Buildings and Improvements       46,082    
Total Initial Acquisition Costs       108,598    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       29,014    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       66,770    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       70,842    
Total Carrying Value 137,612     137,612    
Accumulated Depreciation 44,814     44,814    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 137,612          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 44,814          
Western Region | Vista Del Rey            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       10,670    
Initial Costs, Buildings and Improvements       7,080    
Total Initial Acquisition Costs       17,750    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       2,502    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       10,988    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       9,264    
Total Carrying Value 20,252     20,252    
Accumulated Depreciation 6,117     6,117    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 20,252          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 6,117          
Western Region | Coronado South            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       58,785    
Initial Costs, Buildings and Improvements       50,067    
Total Initial Acquisition Costs       108,852    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       19,393    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       59,278    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       68,967    
Total Carrying Value 128,245     128,245    
Accumulated Depreciation 43,476     43,476    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 128,245          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 43,476          
Western Region | ORANGE COUNTY, CA            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       177,005    
Initial Costs, Land and Land Improvements       351,315    
Initial Costs, Buildings and Improvements       359,742    
Total Initial Acquisition Costs       711,057    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       421,532    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       382,189    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       750,400    
Total Carrying Value 1,132,589     1,132,589    
Accumulated Depreciation 307,438     307,438    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 1,132,589          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 307,438          
Western Region | 2000 Post Street            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       9,861    
Initial Costs, Buildings and Improvements       44,578    
Total Initial Acquisition Costs       54,439    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       30,040    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       13,541    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       70,938    
Total Carrying Value 84,479     84,479    
Accumulated Depreciation 31,789     31,789    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 84,479          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 31,789          
Western Region | Birch Creek            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       4,365    
Initial Costs, Buildings and Improvements       16,696    
Total Initial Acquisition Costs       21,061    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       7,536    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       5,139    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       23,458    
Total Carrying Value 28,597     28,597    
Accumulated Depreciation 13,756     13,756    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 28,597          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 13,756          
Western Region | Highlands Of Marin            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       5,996    
Initial Costs, Buildings and Improvements       24,868    
Total Initial Acquisition Costs       30,864    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       26,063    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       7,257    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       49,670    
Total Carrying Value 56,927     56,927    
Accumulated Depreciation 29,237     29,237    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 56,927          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 29,237          
Western Region | Marina Playa            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       6,224    
Initial Costs, Buildings and Improvements       23,916    
Total Initial Acquisition Costs       30,140    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       10,032    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       6,938    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       33,234    
Total Carrying Value 40,172     40,172    
Accumulated Depreciation 19,547     19,547    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 40,172          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 19,547          
Western Region | The Westerly            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       67,700    
Initial Costs, Land and Land Improvements       48,182    
Initial Costs, Buildings and Improvements       102,364    
Total Initial Acquisition Costs       150,546    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       37,220    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       50,722    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       137,044    
Total Carrying Value 187,766     187,766    
Accumulated Depreciation 46,474     46,474    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 187,766          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 46,474          
Western Region | River Terrace            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       39,310    
Initial Costs, Land and Land Improvements       22,161    
Initial Costs, Buildings and Improvements       40,137    
Total Initial Acquisition Costs       62,298    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       4,307    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       22,428    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       44,177    
Total Carrying Value 66,605     66,605    
Accumulated Depreciation 25,943     25,943    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 66,605          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 25,943          
Western Region | CitySouth            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       14,031    
Initial Costs, Buildings and Improvements       30,537    
Total Initial Acquisition Costs       44,568    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       35,627    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       16,290    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       63,905    
Total Carrying Value 80,195     80,195    
Accumulated Depreciation 36,437     36,437    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 80,195          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 36,437          
Western Region | Bay Terrace            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       8,545    
Initial Costs, Buildings and Improvements       14,458    
Total Initial Acquisition Costs       23,003    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       5,046    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       11,458    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       16,591    
Total Carrying Value 28,049     28,049    
Accumulated Depreciation 9,622     9,622    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 28,049          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 9,622          
Western Region | Highlands of Marin Phase II            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       5,353    
Initial Costs, Buildings and Improvements       18,559    
Total Initial Acquisition Costs       23,912    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       11,088    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       5,758    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       29,242    
Total Carrying Value 35,000     35,000    
Accumulated Depreciation 15,221     15,221    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 35,000          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 15,221          
Western Region | Edgewater            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       30,657    
Initial Costs, Buildings and Improvements       83,872    
Total Initial Acquisition Costs       114,529    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       3,689    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       30,690    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       87,528    
Total Carrying Value 118,218     118,218    
Accumulated Depreciation 39,217     39,217    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 118,218          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 39,217          
Western Region | Almaden Lake Village            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       27,000    
Initial Costs, Land and Land Improvements       594    
Initial Costs, Buildings and Improvements       42,515    
Total Initial Acquisition Costs       43,109    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,031    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       773    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       48,367    
Total Carrying Value 49,140     49,140    
Accumulated Depreciation 21,469     21,469    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 49,140          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 21,469          
Western Region | SAN FRANCISCO, CA            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       66,310    
Initial Costs, Land and Land Improvements       145,665    
Initial Costs, Buildings and Improvements       414,240    
Total Initial Acquisition Costs       559,905    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       274,163    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       158,250    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       675,818    
Total Carrying Value 834,068     834,068    
Accumulated Depreciation 279,168     279,168    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 834,068          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 279,168          
Western Region | Rosebeach            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       8,414    
Initial Costs, Buildings and Improvements       17,449    
Total Initial Acquisition Costs       25,863    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       3,450    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       8,760    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       20,553    
Total Carrying Value 29,313     29,313    
Accumulated Depreciation 12,675     12,675    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 29,313          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 12,675          
Western Region | Other Southern CA [Member]            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       55,263    
Initial Costs, Land and Land Improvements       25,884    
Initial Costs, Buildings and Improvements       37,813    
Total Initial Acquisition Costs       63,697    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       59,789    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       36,164    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       87,322    
Total Carrying Value 123,486     123,486    
Accumulated Depreciation 60,315     60,315    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 123,486          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 60,315          
Western Region | Tierra Del Rey            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       43,078    
Initial Costs, Land and Land Improvements       39,586    
Initial Costs, Buildings and Improvements       36,679    
Total Initial Acquisition Costs       76,265    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       3,250    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       39,674    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       39,841    
Total Carrying Value 79,515     79,515    
Accumulated Depreciation 18,883     18,883    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 79,515          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 18,883          
Western Region | LOS ANGELES, CA            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       110,778    
Initial Costs, Land and Land Improvements       151,833    
Initial Costs, Buildings and Improvements       156,492    
Total Initial Acquisition Costs       308,325    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       134,580    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       160,611    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       282,294    
Total Carrying Value 442,905     442,905    
Accumulated Depreciation 110,320     110,320    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 442,905          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 110,320          
Western Region | Crowne Pointe            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       2,486    
Initial Costs, Buildings and Improvements       6,437    
Total Initial Acquisition Costs       8,923    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       5,666    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       2,868    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       11,721    
Total Carrying Value 14,589     14,589    
Accumulated Depreciation 7,585     7,585    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 14,589          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 7,585          
Western Region | Hilltop            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       2,174    
Initial Costs, Buildings and Improvements       7,408    
Total Initial Acquisition Costs       9,582    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       4,328    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       2,724    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       11,186    
Total Carrying Value 13,910     13,910    
Accumulated Depreciation 6,895     6,895    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 13,910          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 6,895          
Western Region | The Kennedy            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       6,179    
Initial Costs, Buildings and Improvements       22,307    
Total Initial Acquisition Costs       28,486    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       1,931    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       6,272    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       24,145    
Total Carrying Value 30,417     30,417    
Accumulated Depreciation 13,947     13,947    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 30,417          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 13,947          
Western Region | Hearthstone at Merrill Creek            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       22,591    
Initial Costs, Land and Land Improvements       6,848    
Initial Costs, Buildings and Improvements       30,922    
Total Initial Acquisition Costs       37,770    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       3,829    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       6,975    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       34,624    
Total Carrying Value 41,599     41,599    
Accumulated Depreciation 15,574     15,574    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 41,599          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 15,574          
Western Region | Island Square            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       21,284    
Initial Costs, Buildings and Improvements       89,389    
Total Initial Acquisition Costs       110,673    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       4,695    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       21,428    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       93,940    
Total Carrying Value 115,368     115,368    
Accumulated Depreciation 40,021     40,021    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 115,368          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 40,021          
Western Region | SEATTLE, WA            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       57,525    
Initial Costs, Land and Land Improvements       103,975    
Initial Costs, Buildings and Improvements       443,344    
Total Initial Acquisition Costs       547,319    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       35,758    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       108,280    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       474,797    
Total Carrying Value 583,077     583,077    
Accumulated Depreciation 181,530     181,530    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 583,077          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 181,530          
Western Region | Villas at Carlsbad            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       6,517    
Initial Costs, Buildings and Improvements       10,718    
Total Initial Acquisition Costs       17,235    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       2,876    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       6,780    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       13,331    
Total Carrying Value 20,111     20,111    
Accumulated Depreciation 7,826     7,826    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 20,111          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 7,826          
Western Region | Boronda Manor            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       1,946    
Initial Costs, Buildings and Improvements       8,982    
Total Initial Acquisition Costs       10,928    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       9,534    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       3,195    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       17,267    
Total Carrying Value 20,462     20,462    
Accumulated Depreciation 9,244     9,244    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 20,462          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 9,244          
Western Region | Garden Court            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       888    
Initial Costs, Buildings and Improvements       4,188    
Total Initial Acquisition Costs       5,076    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       5,435    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       1,559    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       8,952    
Total Carrying Value 10,511     10,511    
Accumulated Depreciation 4,981     4,981    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 10,511          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 4,981          
Western Region | Cambridge Court            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       3,039    
Initial Costs, Buildings and Improvements       12,883    
Total Initial Acquisition Costs       15,922    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       14,767    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       5,302    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       25,387    
Total Carrying Value 30,689     30,689    
Accumulated Depreciation 13,958     13,958    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 30,689          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 13,958          
Western Region | Laurel Tree            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       1,304    
Initial Costs, Buildings and Improvements       5,115    
Total Initial Acquisition Costs       6,419    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,080    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       2,188    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       10,311    
Total Carrying Value 12,499     12,499    
Accumulated Depreciation 5,627     5,627    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 12,499          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 5,627          
Western Region | The Pointe At Harden Ranch            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       6,388    
Initial Costs, Buildings and Improvements       23,854    
Total Initial Acquisition Costs       30,242    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       27,357    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       10,021    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       47,578    
Total Carrying Value 57,599     57,599    
Accumulated Depreciation 24,926     24,926    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 57,599          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 24,926          
Western Region | The Pointe At Northridge            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       2,044    
Initial Costs, Buildings and Improvements       8,028    
Total Initial Acquisition Costs       10,072    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       10,089    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       3,295    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       16,866    
Total Carrying Value 20,161     20,161    
Accumulated Depreciation 9,293     9,293    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 20,161          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 9,293          
Western Region | The Pointe At Westlake            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       1,329    
Initial Costs, Buildings and Improvements       5,334    
Total Initial Acquisition Costs       6,663    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,364    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       2,181    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       10,846    
Total Carrying Value 13,027     13,027    
Accumulated Depreciation 5,700     5,700    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 13,027          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 5,700          
Western Region | MONTEREY PENINSULA, CA            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       16,938    
Initial Costs, Buildings and Improvements       68,384    
Total Initial Acquisition Costs       85,322    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       79,626    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       27,741    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       137,207    
Total Carrying Value 164,948     164,948    
Accumulated Depreciation 73,729     73,729    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 164,948          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 73,729          
Western Region | Verano at Rancho Cucamonga Town Square            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       55,263    
Initial Costs, Land and Land Improvements       13,557    
Initial Costs, Buildings and Improvements       3,645    
Total Initial Acquisition Costs       17,202    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       53,949    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       23,255    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       47,896    
Total Carrying Value 71,151     71,151    
Accumulated Depreciation 34,875     34,875    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 71,151          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 34,875          
Western Region | Tualatin Heights            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       3,273    
Initial Costs, Buildings and Improvements       9,134    
Total Initial Acquisition Costs       12,407    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,745    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       3,841    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       15,311    
Total Carrying Value 19,152     19,152    
Accumulated Depreciation 10,231     10,231    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 19,152          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 10,231          
Western Region | Hunt Club            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       6,014    
Initial Costs, Buildings and Improvements       14,870    
Total Initial Acquisition Costs       20,884    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,866    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       6,395    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       21,355    
Total Carrying Value 27,750     27,750    
Accumulated Depreciation 14,364     14,364    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 27,750          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 14,364          
Western Region | PORTLAND, OR            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       9,287    
Initial Costs, Buildings and Improvements       24,004    
Total Initial Acquisition Costs       33,291    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       13,611    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       10,236    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       36,666    
Total Carrying Value 46,902     46,902    
Accumulated Depreciation 24,595     24,595    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 46,902          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 24,595          
Mid Atlantic Region            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       507,412    
Initial Costs, Land and Land Improvements       388,304    
Initial Costs, Buildings and Improvements       1,550,755    
Total Initial Acquisition Costs       1,939,059    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       598,125    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       464,660    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       2,072,524    
Total Carrying Value 2,537,184     2,537,184    
Accumulated Depreciation 647,723     647,723    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 2,537,184          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 647,723          
Mid Atlantic Region | The Whitmore            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       6,418    
Initial Costs, Buildings and Improvements       13,411    
Total Initial Acquisition Costs       19,829    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       20,734    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       7,495    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       33,068    
Total Carrying Value 40,563     40,563    
Accumulated Depreciation 22,988     22,988    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 40,563          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 22,988          
Mid Atlantic Region | Ridgewood            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       5,612    
Initial Costs, Buildings and Improvements       20,086    
Total Initial Acquisition Costs       25,698    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       8,522    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       6,014    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       28,206    
Total Carrying Value 34,220     34,220    
Accumulated Depreciation 20,340     20,340    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 34,220          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 20,340          
Mid Atlantic Region | Wellington Place at Olde Town            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       32,037    
Initial Costs, Land and Land Improvements       13,753    
Initial Costs, Buildings and Improvements       36,059    
Total Initial Acquisition Costs       49,812    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       17,416    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       14,740    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       52,488    
Total Carrying Value 67,228     67,228    
Accumulated Depreciation 35,000     35,000    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 67,228          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 35,000          
Mid Atlantic Region | Andover House            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       14,357    
Initial Costs, Buildings and Improvements       51,577    
Total Initial Acquisition Costs       65,934    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       3,769    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       14,379    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       55,324    
Total Carrying Value 69,703     69,703    
Accumulated Depreciation 27,837     27,837    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 69,703          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 27,837          
Mid Atlantic Region | Sullivan Place            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       1,137    
Initial Costs, Buildings and Improvements       103,676    
Total Initial Acquisition Costs       104,813    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       7,066    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       1,364    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       110,515    
Total Carrying Value 111,879     111,879    
Accumulated Depreciation 51,643     51,643    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 111,879          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 51,643          
Mid Atlantic Region | Courts at Huntington Station [Member]            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       27,749    
Initial Costs, Buildings and Improvements       111,878    
Total Initial Acquisition Costs       139,627    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       78    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       27,749    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       111,956    
Total Carrying Value 139,705     139,705    
Accumulated Depreciation 1,682     1,682    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 139,705          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 1,682          
Mid Atlantic Region | Circle Towers            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       70,884    
Initial Costs, Land and Land Improvements       32,815    
Initial Costs, Buildings and Improvements       107,051    
Total Initial Acquisition Costs       139,866    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       13,056    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       33,357    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       119,565    
Total Carrying Value 152,922     152,922    
Accumulated Depreciation 53,022     53,022    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 152,922          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 53,022          
Mid Atlantic Region | Delancey at Shirlington            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       21,606    
Initial Costs, Buildings and Improvements       66,765    
Total Initial Acquisition Costs       88,371    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       2,195    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       21,632    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       68,934    
Total Carrying Value 90,566     90,566    
Accumulated Depreciation 30,609     30,609    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 90,566          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 30,609          
Mid Atlantic Region | METROPOLITAN DC            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       407,067    
Initial Costs, Land and Land Improvements       345,666    
Initial Costs, Buildings and Improvements       1,307,924    
Total Initial Acquisition Costs       1,653,590    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       454,931    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       406,934    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       1,701,587    
Total Carrying Value 2,108,521     2,108,521    
Accumulated Depreciation 403,882     403,882    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 2,108,521          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 403,882          
Mid Atlantic Region | Lakeside Mill            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       12,569    
Initial Costs, Land and Land Improvements       2,666    
Initial Costs, Buildings and Improvements       10,109    
Total Initial Acquisition Costs       12,775    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       5,038    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       2,997    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       14,816    
Total Carrying Value 17,813     17,813    
Accumulated Depreciation 11,336     11,336    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 17,813          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 11,336          
Mid Atlantic Region | Calvert’s Walk            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       4,408    
Initial Costs, Buildings and Improvements       24,692    
Total Initial Acquisition Costs       29,100    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       7,396    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       4,817    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       31,679    
Total Carrying Value 36,496     36,496    
Accumulated Depreciation 20,827     20,827    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 36,496          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 20,827          
Mid Atlantic Region | Liriope Apartments            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       1,620    
Initial Costs, Buildings and Improvements       6,791    
Total Initial Acquisition Costs       8,411    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       1,374    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       1,653    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       8,132    
Total Carrying Value 9,785     9,785    
Accumulated Depreciation 5,352     5,352    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 9,785          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 5,352          
Mid Atlantic Region | 20 Lambourne            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       30,132    
Initial Costs, Land and Land Improvements       11,750    
Initial Costs, Buildings and Improvements       45,590    
Total Initial Acquisition Costs       57,340    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,406    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       12,106    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       51,640    
Total Carrying Value 63,746     63,746    
Accumulated Depreciation 24,313     24,313    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 63,746          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 24,313          
Mid Atlantic Region | BALTIMORE, MD            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       65,778    
Initial Costs, Land and Land Improvements       37,515    
Initial Costs, Buildings and Improvements       181,923    
Total Initial Acquisition Costs       219,438    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       67,997    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       43,088    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       244,347    
Total Carrying Value 287,435     287,435    
Accumulated Depreciation 146,424     146,424    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 287,435          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 146,424          
Mid Atlantic Region | DelRey Tower [Member]            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       297    
Initial Costs, Buildings and Improvements       12,786    
Total Initial Acquisition Costs       13,083    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       113,357    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       9,461    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       116,979    
Total Carrying Value 126,440     126,440    
Accumulated Depreciation 9,914     9,914    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 126,440          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 9,914          
Southeastern Region            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       170,986    
Initial Costs, Land and Land Improvements       86,349    
Initial Costs, Buildings and Improvements       355,426    
Total Initial Acquisition Costs       441,775    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       288,284    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       118,304    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       611,755    
Total Carrying Value 730,059     730,059    
Accumulated Depreciation 425,591     425,591    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 730,059          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 425,591          
Southeastern Region | Inlet Bay            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       7,702    
Initial Costs, Buildings and Improvements       23,150    
Total Initial Acquisition Costs       30,852    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       15,659    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       9,304    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       37,207    
Total Carrying Value 46,511     46,511    
Accumulated Depreciation 27,055     27,055    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 46,511          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 27,055          
Southeastern Region | MacAlpine Place            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       10,869    
Initial Costs, Buildings and Improvements       36,858    
Total Initial Acquisition Costs       47,727    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       7,862    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       11,545    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       44,044    
Total Carrying Value 55,589     55,589    
Accumulated Depreciation 28,780     28,780    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 55,589          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 28,780          
Southeastern Region | TAMPA, FL            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       30,943    
Initial Costs, Land and Land Improvements       32,324    
Initial Costs, Buildings and Improvements       122,652    
Total Initial Acquisition Costs       154,976    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       85,244    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       48,373    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       191,847    
Total Carrying Value 240,220     240,220    
Accumulated Depreciation 131,728     131,728    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 240,220          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 131,728          
Southeastern Region | Legacy Hill            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       1,148    
Initial Costs, Buildings and Improvements       5,867    
Total Initial Acquisition Costs       7,015    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       8,807    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       1,764    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       14,058    
Total Carrying Value 15,822     15,822    
Accumulated Depreciation 11,246     11,246    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 15,822          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 11,246          
Southeastern Region | Hickory Run            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       1,469    
Initial Costs, Buildings and Improvements       11,584    
Total Initial Acquisition Costs       13,053    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       10,459    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       2,155    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       21,357    
Total Carrying Value 23,512     23,512    
Accumulated Depreciation 14,244     14,244    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 23,512          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 14,244          
Southeastern Region | Carrington Hills            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       2,117    
Initial Costs, Buildings and Improvements       0    
Total Initial Acquisition Costs       2,117    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       34,535    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       4,506    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       32,146    
Total Carrying Value 36,652     36,652    
Accumulated Depreciation 21,305     21,305    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 36,652          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 21,305          
Southeastern Region | Brookridge            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       708    
Initial Costs, Buildings and Improvements       5,461    
Total Initial Acquisition Costs       6,169    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       4,830    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       1,162    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       9,837    
Total Carrying Value 10,999     10,999    
Accumulated Depreciation 7,007     7,007    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 10,999          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 7,007          
Southeastern Region | Breckenridge            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       766    
Initial Costs, Buildings and Improvements       7,714    
Total Initial Acquisition Costs       8,480    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       4,646    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       1,285    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       11,841    
Total Carrying Value 13,126     13,126    
Accumulated Depreciation 8,155     8,155    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 13,126          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 8,155          
Southeastern Region | Polo Park            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       4,583    
Initial Costs, Buildings and Improvements       16,293    
Total Initial Acquisition Costs       20,876    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       16,508    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       5,741    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       31,643    
Total Carrying Value 37,384     37,384    
Accumulated Depreciation 22,411     22,411    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 37,384          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 22,411          
Southeastern Region | NASHVILLE, TN            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       38,481    
Initial Costs, Land and Land Improvements       15,433    
Initial Costs, Buildings and Improvements       87,608    
Total Initial Acquisition Costs       103,041    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       92,982    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       22,206    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       173,817    
Total Carrying Value 196,023     196,023    
Accumulated Depreciation 117,692     117,692    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 196,023          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 117,692          
Southeastern Region | The Reserve and Park at Riverbridge            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       39,179    
Initial Costs, Land and Land Improvements       15,968    
Initial Costs, Buildings and Improvements       56,401    
Total Initial Acquisition Costs       72,369    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       9,823    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       16,602    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       65,590    
Total Carrying Value 82,192     82,192    
Accumulated Depreciation 40,676     40,676    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 82,192          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 40,676          
Southeastern Region | OTHER FLORIDA            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       39,179    
Initial Costs, Land and Land Improvements       15,968    
Initial Costs, Buildings and Improvements       56,401    
Total Initial Acquisition Costs       72,369    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       9,823    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       16,602    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       65,590    
Total Carrying Value 82,192     82,192    
Accumulated Depreciation 40,676     40,676    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 82,192          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 40,676          
Northeast Region            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       77,066    
Initial Costs, Land and Land Improvements       317,831    
Initial Costs, Buildings and Improvements       1,182,479    
Total Initial Acquisition Costs       1,500,310    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       337,084    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       317,479    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       1,519,915    
Total Carrying Value 1,837,394     1,837,394    
Accumulated Depreciation 344,653     344,653    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 1,837,394          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 344,653          
Northeast Region | Inwood West            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       54,919    
Initial Costs, Land and Land Improvements       20,778    
Initial Costs, Buildings and Improvements       88,096    
Total Initial Acquisition Costs       108,874    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       5,121    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       19,324    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       94,671    
Total Carrying Value 113,995     113,995    
Accumulated Depreciation 26,028     26,028    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 113,995          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 26,028          
Northeast Region | 14 North            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       10,961    
Initial Costs, Buildings and Improvements       51,175    
Total Initial Acquisition Costs       62,136    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,359    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       11,077    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       57,418    
Total Carrying Value 68,495     68,495    
Accumulated Depreciation 16,632     16,632    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 68,495          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 16,632          
Northeast Region | BOSTON, MA            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       77,066    
Initial Costs, Land and Land Improvements       67,953    
Initial Costs, Buildings and Improvements       265,167    
Total Initial Acquisition Costs       333,120    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       210,880    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       66,733    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       477,267    
Total Carrying Value 544,000     544,000    
Accumulated Depreciation 90,744     90,744    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 544,000          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 90,744          
Northeast Region | 10 Hanover Square            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       41,432    
Initial Costs, Buildings and Improvements       218,983    
Total Initial Acquisition Costs       260,415    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       9,730    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       41,496    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       228,649    
Total Carrying Value 270,145     270,145    
Accumulated Depreciation 54,457     54,457    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 270,145          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 54,457          
Northeast Region | 95 Wall Street            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       57,637    
Initial Costs, Buildings and Improvements       266,255    
Total Initial Acquisition Costs       323,892    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       7,110    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       57,810    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       273,192    
Total Carrying Value 331,002     331,002    
Accumulated Depreciation 71,769     71,769    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 331,002          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 71,769          
Northeast Region | NEW YORK, NY            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       249,878    
Initial Costs, Buildings and Improvements       917,312    
Total Initial Acquisition Costs       1,167,190    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       126,204    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       250,746    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       1,042,648    
Total Carrying Value 1,293,394     1,293,394    
Accumulated Depreciation 253,909     253,909    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 1,293,394          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 253,909          
Southwestern Region            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       148,394    
Initial Costs, Land and Land Improvements       99,870    
Initial Costs, Buildings and Improvements       257,677    
Total Initial Acquisition Costs       357,547    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       89,898    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       115,906    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       331,539    
Total Carrying Value 447,445     447,445    
Accumulated Depreciation 170,852     170,852    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 447,445          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 170,852          
Southwestern Region | THIRTY377            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       29,361    
Initial Costs, Land and Land Improvements       24,036    
Initial Costs, Buildings and Improvements       32,951    
Total Initial Acquisition Costs       56,987    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       9,332    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       24,382    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       41,937    
Total Carrying Value 66,319     66,319    
Accumulated Depreciation 24,256     24,256    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 66,319          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 24,256          
Southwestern Region | Legacy Village            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       82,734    
Initial Costs, Land and Land Improvements       16,882    
Initial Costs, Buildings and Improvements       100,102    
Total Initial Acquisition Costs       116,984    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       8,827    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       17,407    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       108,404    
Total Carrying Value 125,811     125,811    
Accumulated Depreciation 50,919     50,919    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 125,811          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 50,919          
Southwestern Region | DALLAS, TX            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       112,095    
Initial Costs, Land and Land Improvements       83,453    
Initial Costs, Buildings and Improvements       153,637    
Total Initial Acquisition Costs       237,090    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       60,036    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       97,144    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       199,982    
Total Carrying Value 297,126     297,126    
Accumulated Depreciation 112,394     112,394    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 297,126          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 112,394          
Southwestern Region | Barton Creek Landing            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       3,151    
Initial Costs, Buildings and Improvements       14,269    
Total Initial Acquisition Costs       17,420    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       22,588    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       4,913    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       35,095    
Total Carrying Value 40,008     40,008    
Accumulated Depreciation 22,924     22,924    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 40,008          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 22,924          
Southwestern Region | AUSTIN, TX            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       36,299    
Initial Costs, Land and Land Improvements       16,417    
Initial Costs, Buildings and Improvements       104,040    
Total Initial Acquisition Costs       120,457    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       29,862    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       18,762    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       131,557    
Total Carrying Value 150,319     150,319    
Accumulated Depreciation 58,458     58,458    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 150,319          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 58,458          
United Dominion Reality L.P.            
Real Estate and Accumulated Depreciation [Line Items]            
Deferred Finance Costs, Net       (2,199) (4,500)  
Total Carrying Value 4,238,770 4,188,480 4,182,920 3,630,905 4,238,770 4,188,480
Accumulated Depreciation 1,403,303 1,241,574 1,097,133 1,281,258 1,403,303 1,241,574
Aggregate cost for federal income tax purposes       3,000,000    
Real Estate Owned, Gross [Roll Forward]            
Balance at beginning of the year 4,238,770 4,188,480 4,182,920      
Real estate acquired 139,627   0      
Capital expenditures and development 61,196 91,682 151,002      
Real estate sold (180,069) (41,013) (70,687)      
Real Estate Investment Property, at Cost       3,630,905 4,238,770  
Hurricane related impairment of assets (140) (379) 0      
Balance at end of the year 3,630,905 4,238,770 4,188,480      
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at beginning of the year 1,403,303 1,241,574 1,097,133      
Depreciation expense for the year 168,495 178,719 179,404      
Accumulated depreciation on sales (67,177) (16,674) (34,794)      
Write off of accumulated depreciation on hurricane related impaired assets 0 (316) 0      
Balance at end of year $ 1,281,258 1,403,303 1,241,574      
United Dominion Reality L.P. | Estimated depreciable lives of buildings range beginning            
Real Estate and Accumulated Depreciation [Line Items]            
Depreciable life for all buildings 35 years          
United Dominion Reality L.P. | Estimated depreciable lives of buildings range end            
Real Estate and Accumulated Depreciation [Line Items]            
Depreciable life for all buildings 55 years          
United Dominion Reality L.P. | Los Alisos            
Real Estate Owned, Gross [Roll Forward]            
Retirement of fully depreciated assets $ 0 0 (74,755)      
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Accumulated depreciation on retirements of fully depreciated asset 0 0 (169)      
United Dominion Reality L.P. | Other            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances [2]       0    
Initial Costs, Land and Land Improvements [2]       0    
Initial Costs, Buildings and Improvements [2]       0    
Total Initial Acquisition Costs [2]       0    
Costs of Improvements Capitalized Subsequent to Acquisition Costs [2]       1,093    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements [2]       0    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements [2]       1,093    
Total Carrying Value [2] 1,093     1,093    
Accumulated Depreciation [2] 0     0    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year [2] 1,093          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year [2] 0          
United Dominion Reality L.P. | TOTAL CORPORATE            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       0    
Initial Costs, Buildings and Improvements       0    
Total Initial Acquisition Costs       0    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       1,093    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       0    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       1,093    
Total Carrying Value 1,093     1,093    
Accumulated Depreciation 0     0    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 1,093          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 0          
United Dominion Reality L.P. | Commercial Held for Development            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       1,407    
Initial Costs, Buildings and Improvements       0    
Total Initial Acquisition Costs       1,407    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,021    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       1,380    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       6,048    
Total Carrying Value 7,428     7,428    
Accumulated Depreciation 2,683     2,683    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 7,428          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 2,683          
United Dominion Reality L.P. | Commercial Held for Development | Office Building [Member]            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       1,407    
Initial Costs, Buildings and Improvements       0    
Total Initial Acquisition Costs       1,407    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,021    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       1,380    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       6,048    
Total Carrying Value 7,428     7,428    
Accumulated Depreciation 2,683     2,683    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 7,428          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 2,683          
United Dominion Reality L.P. | Commercial Held for Development | TOTAL COMMERCIAL & CORPORATE            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       1,407    
Initial Costs, Buildings and Improvements       0    
Total Initial Acquisition Costs       1,407    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       7,114    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       1,380    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       7,141    
Total Carrying Value 8,521     8,521    
Accumulated Depreciation 2,683     2,683    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 8,521          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 2,683          
United Dominion Reality L.P. | Commercial Held for Development | Total Real Estate Owned            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       475,964    
Initial Costs, Land and Land Improvements       748,578    
Initial Costs, Buildings and Improvements       2,082,113    
Total Initial Acquisition Costs       2,830,691    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       812,808    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       833,300    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       2,797,605    
Total Carrying Value 3,630,905     3,630,905    
Accumulated Depreciation 1,281,258     1,281,258    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 3,630,905          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 1,281,258          
United Dominion Reality L.P. | Western Region            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       364,246    
Initial Costs, Land and Land Improvements       508,462    
Initial Costs, Buildings and Improvements       959,128    
Total Initial Acquisition Costs       1,467,590    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       498,944    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       572,193    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       1,381,812    
Total Carrying Value 1,954,005     1,954,005    
Accumulated Depreciation 746,659     746,659    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 1,954,005          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 746,659          
United Dominion Reality L.P. | Western Region | Harbor at Mesa Verde            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       61,050    
Initial Costs, Land and Land Improvements       20,476    
Initial Costs, Buildings and Improvements       28,538    
Total Initial Acquisition Costs       49,014    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       14,641    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       21,314    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       42,341    
Total Carrying Value 63,655     63,655    
Accumulated Depreciation 27,697     27,697    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 63,655          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 27,697          
United Dominion Reality L.P. | Western Region | 27 Seventy FIve Mesa Verde [Member]            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       36,423    
Initial Costs, Land and Land Improvements       99,329    
Initial Costs, Buildings and Improvements       110,644    
Total Initial Acquisition Costs       209,973    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       92,673    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       112,650    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       189,996    
Total Carrying Value 302,646     302,646    
Accumulated Depreciation 87,007     87,007    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 302,646          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 87,007          
United Dominion Reality L.P. | Western Region | Pacific Shores            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       42,552    
Initial Costs, Land and Land Improvements       7,345    
Initial Costs, Buildings and Improvements       22,624    
Total Initial Acquisition Costs       29,969    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       9,913    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       7,913    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       31,969    
Total Carrying Value 39,882     39,882    
Accumulated Depreciation 20,771     20,771    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 39,882          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 20,771          
United Dominion Reality L.P. | Western Region | Huntington Vista            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       36,980    
Initial Costs, Land and Land Improvements       8,055    
Initial Costs, Buildings and Improvements       22,486    
Total Initial Acquisition Costs       30,541    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       11,612    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       8,713    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       33,440    
Total Carrying Value 42,153     42,153    
Accumulated Depreciation 19,810     19,810    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 42,153          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 19,810          
United Dominion Reality L.P. | Western Region | Missions at Back Bay            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       229    
Initial Costs, Buildings and Improvements       14,129    
Total Initial Acquisition Costs       14,358    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       2,526    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       10,874    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       6,010    
Total Carrying Value 16,884     16,884    
Accumulated Depreciation 4,229     4,229    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 16,884          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 4,229          
United Dominion Reality L.P. | Western Region | Coronado at Newport — North            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       62,516    
Initial Costs, Buildings and Improvements       46,082    
Total Initial Acquisition Costs       108,598    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       29,014    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       66,770    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       70,842    
Total Carrying Value 137,612     137,612    
Accumulated Depreciation 44,814     44,814    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 137,612          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 44,814          
United Dominion Reality L.P. | Western Region | Vista Del Rey            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       10,670    
Initial Costs, Buildings and Improvements       7,080    
Total Initial Acquisition Costs       17,750    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       2,502    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       10,988    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       9,264    
Total Carrying Value 20,252     20,252    
Accumulated Depreciation 6,117     6,117    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 20,252          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 6,117          
United Dominion Reality L.P. | Western Region | Coronado South            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       58,785    
Initial Costs, Buildings and Improvements       50,067    
Total Initial Acquisition Costs       108,852    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       19,393    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       59,278    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       68,967    
Total Carrying Value 128,245     128,245    
Accumulated Depreciation 43,476     43,476    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 128,245          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 43,476          
United Dominion Reality L.P. | Western Region | ORANGE COUNTY, CA            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       177,005    
Initial Costs, Land and Land Improvements       267,405    
Initial Costs, Buildings and Improvements       301,650    
Total Initial Acquisition Costs       569,055    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       182,274    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       298,500    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       452,829    
Total Carrying Value 751,329     751,329    
Accumulated Depreciation 253,921     253,921    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 751,329          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 253,921          
United Dominion Reality L.P. | Western Region | 2000 Post Street            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       9,861    
Initial Costs, Buildings and Improvements       44,578    
Total Initial Acquisition Costs       54,439    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       30,040    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       10,249    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       61,701    
Total Carrying Value 71,950     71,950    
Accumulated Depreciation 25,684     25,684    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 71,950          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 25,684          
United Dominion Reality L.P. | Western Region | Birch Creek            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       4,365    
Initial Costs, Buildings and Improvements       16,696    
Total Initial Acquisition Costs       21,061    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       7,536    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       5,139    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       23,458    
Total Carrying Value 28,597     28,597    
Accumulated Depreciation 13,756     13,756    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 28,597          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 13,756          
United Dominion Reality L.P. | Western Region | Highlands Of Marin            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       5,996    
Initial Costs, Buildings and Improvements       24,868    
Total Initial Acquisition Costs       30,864    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       26,063    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       7,257    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       49,670    
Total Carrying Value 56,927     56,927    
Accumulated Depreciation 29,237     29,237    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 56,927          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 29,237          
United Dominion Reality L.P. | Western Region | Marina Playa            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       6,224    
Initial Costs, Buildings and Improvements       23,916    
Total Initial Acquisition Costs       30,140    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       10,032    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       6,938    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       33,234    
Total Carrying Value 40,172     40,172    
Accumulated Depreciation 19,547     19,547    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 40,172          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 19,547          
United Dominion Reality L.P. | Western Region | River Terrace            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       39,310    
Initial Costs, Land and Land Improvements       22,161    
Initial Costs, Buildings and Improvements       40,137    
Total Initial Acquisition Costs       62,298    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       4,307    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       22,428    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       44,177    
Total Carrying Value 66,605     66,605    
Accumulated Depreciation 25,943     25,943    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 66,605          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 25,943          
United Dominion Reality L.P. | Western Region | CitySouth            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       14,031    
Initial Costs, Buildings and Improvements       30,537    
Total Initial Acquisition Costs       44,568    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       35,627    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       16,290    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       63,905    
Total Carrying Value 80,195     80,195    
Accumulated Depreciation 36,437     36,437    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 80,195          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 36,437          
United Dominion Reality L.P. | Western Region | Bay Terrace            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       8,545    
Initial Costs, Buildings and Improvements       14,458    
Total Initial Acquisition Costs       23,003    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       5,046    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       11,458    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       16,591    
Total Carrying Value 28,049     28,049    
Accumulated Depreciation 9,622     9,622    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 28,049          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 9,622          
United Dominion Reality L.P. | Western Region | Highlands of Marin Phase II            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       5,353    
Initial Costs, Buildings and Improvements       18,559    
Total Initial Acquisition Costs       23,912    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       11,088    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       5,758    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       29,242    
Total Carrying Value 35,000     35,000    
Accumulated Depreciation 15,221     15,221    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 35,000          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 15,221          
United Dominion Reality L.P. | Western Region | Edgewater            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       30,657    
Initial Costs, Buildings and Improvements       83,872    
Total Initial Acquisition Costs       114,529    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       3,689    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       30,690    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       87,528    
Total Carrying Value 118,218     118,218    
Accumulated Depreciation 39,217     39,217    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 118,218          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 39,217          
United Dominion Reality L.P. | Western Region | Almaden Lake Village            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       27,000    
Initial Costs, Land and Land Improvements       594    
Initial Costs, Buildings and Improvements       42,515    
Total Initial Acquisition Costs       43,109    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,031    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       773    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       48,367    
Total Carrying Value 49,140     49,140    
Accumulated Depreciation 21,469     21,469    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 49,140          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 21,469          
United Dominion Reality L.P. | Western Region | SAN FRANCISCO, CA            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       66,310    
Initial Costs, Land and Land Improvements       107,787    
Initial Costs, Buildings and Improvements       340,136    
Total Initial Acquisition Costs       447,923    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       139,459    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       116,980    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       457,873    
Total Carrying Value 574,853     574,853    
Accumulated Depreciation 236,133     236,133    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 574,853          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 236,133          
United Dominion Reality L.P. | Western Region | Rosebeach            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       8,414    
Initial Costs, Buildings and Improvements       17,449    
Total Initial Acquisition Costs       25,863    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       3,450    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       8,760    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       20,553    
Total Carrying Value 29,313     29,313    
Accumulated Depreciation 12,675     12,675    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 29,313          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 12,675          
United Dominion Reality L.P. | Western Region | Other Southern CA [Member]            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       55,262    
Initial Costs, Land and Land Improvements       20,074    
Initial Costs, Buildings and Improvements       14,363    
Total Initial Acquisition Costs       34,437    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       56,825    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       30,035    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       61,227    
Total Carrying Value 91,262     91,262    
Accumulated Depreciation 42,701     42,701    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 91,262          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 42,701          
United Dominion Reality L.P. | Western Region | Tierra Del Rey            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       43,078    
Initial Costs, Land and Land Improvements       39,586    
Initial Costs, Buildings and Improvements       36,679    
Total Initial Acquisition Costs       76,265    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       3,250    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       39,674    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       39,841    
Total Carrying Value 79,515     79,515    
Accumulated Depreciation 18,883     18,883    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 79,515          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 18,883          
United Dominion Reality L.P. | Western Region | LOS ANGELES, CA            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       43,078    
Initial Costs, Land and Land Improvements       48,000    
Initial Costs, Buildings and Improvements       54,128    
Total Initial Acquisition Costs       102,128    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,700    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       48,434    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       60,394    
Total Carrying Value 108,828     108,828    
Accumulated Depreciation 31,558     31,558    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 108,828          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 31,558          
United Dominion Reality L.P. | Western Region | Crowne Pointe            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       2,486    
Initial Costs, Buildings and Improvements       6,437    
Total Initial Acquisition Costs       8,923    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       5,666    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       2,868    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       11,721    
Total Carrying Value 14,589     14,589    
Accumulated Depreciation 7,585     7,585    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 14,589          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 7,585          
United Dominion Reality L.P. | Western Region | Hilltop            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       2,174    
Initial Costs, Buildings and Improvements       7,408    
Total Initial Acquisition Costs       9,582    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       4,328    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       2,724    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       11,186    
Total Carrying Value 13,910     13,910    
Accumulated Depreciation 6,895     6,895    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 13,910          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 6,895          
United Dominion Reality L.P. | Western Region | The Kennedy            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       6,179    
Initial Costs, Buildings and Improvements       22,307    
Total Initial Acquisition Costs       28,486    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       1,931    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       6,272    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       24,145    
Total Carrying Value 30,417     30,417    
Accumulated Depreciation 13,947     13,947    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 30,417          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 13,947          
United Dominion Reality L.P. | Western Region | Hearthstone at Merrill Creek            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       22,591    
Initial Costs, Land and Land Improvements       6,848    
Initial Costs, Buildings and Improvements       30,922    
Total Initial Acquisition Costs       37,770    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       3,829    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       6,975    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       34,624    
Total Carrying Value 41,599     41,599    
Accumulated Depreciation 15,574     15,574    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 41,599          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 15,574          
United Dominion Reality L.P. | Western Region | Island Square            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       21,284    
Initial Costs, Buildings and Improvements       89,389    
Total Initial Acquisition Costs       110,673    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       4,695    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       21,428    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       93,940    
Total Carrying Value 115,368     115,368    
Accumulated Depreciation 40,021     40,021    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 115,368          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 40,021          
United Dominion Reality L.P. | Western Region | SEATTLE, WA            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       22,591    
Initial Costs, Land and Land Improvements       38,971    
Initial Costs, Buildings and Improvements       156,463    
Total Initial Acquisition Costs       195,434    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       20,449    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       40,267    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       175,616    
Total Carrying Value 215,883     215,883    
Accumulated Depreciation 84,022     84,022    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 215,883          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 84,022          
United Dominion Reality L.P. | Western Region | Villas at Carlsbad            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       6,517    
Initial Costs, Buildings and Improvements       10,718    
Total Initial Acquisition Costs       17,235    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       2,876    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       6,780    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       13,331    
Total Carrying Value 20,111     20,111    
Accumulated Depreciation 7,826     7,826    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 20,111          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 7,826          
United Dominion Reality L.P. | Western Region | Boronda Manor            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       1,946    
Initial Costs, Buildings and Improvements       8,982    
Total Initial Acquisition Costs       10,928    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       9,534    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       3,195    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       17,267    
Total Carrying Value 20,462     20,462    
Accumulated Depreciation 9,244     9,244    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 20,462          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 9,244          
United Dominion Reality L.P. | Western Region | Garden Court            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       888    
Initial Costs, Buildings and Improvements       4,188    
Total Initial Acquisition Costs       5,076    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       5,435    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       1,559    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       8,952    
Total Carrying Value 10,511     10,511    
Accumulated Depreciation 4,981     4,981    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 10,511          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 4,981          
United Dominion Reality L.P. | Western Region | Cambridge Court            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       3,039    
Initial Costs, Buildings and Improvements       12,883    
Total Initial Acquisition Costs       15,922    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       14,767    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       5,302    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       25,387    
Total Carrying Value 30,689     30,689    
Accumulated Depreciation 13,958     13,958    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 30,689          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 13,958          
United Dominion Reality L.P. | Western Region | Laurel Tree            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       1,304    
Initial Costs, Buildings and Improvements       5,115    
Total Initial Acquisition Costs       6,419    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,080    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       2,188    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       10,311    
Total Carrying Value 12,499     12,499    
Accumulated Depreciation 5,627     5,627    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 12,499          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 5,627          
United Dominion Reality L.P. | Western Region | The Pointe At Harden Ranch            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       6,388    
Initial Costs, Buildings and Improvements       23,854    
Total Initial Acquisition Costs       30,242    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       27,357    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       10,021    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       47,578    
Total Carrying Value 57,599     57,599    
Accumulated Depreciation 24,926     24,926    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 57,599          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 24,926          
United Dominion Reality L.P. | Western Region | The Pointe At Northridge            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       2,044    
Initial Costs, Buildings and Improvements       8,028    
Total Initial Acquisition Costs       10,072    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       10,089    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       3,295    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       16,866    
Total Carrying Value 20,161     20,161    
Accumulated Depreciation 9,293     9,293    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 20,161          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 9,293          
United Dominion Reality L.P. | Western Region | The Pointe At Westlake            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       1,329    
Initial Costs, Buildings and Improvements       5,334    
Total Initial Acquisition Costs       6,663    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,364    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       2,181    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       10,846    
Total Carrying Value 13,027     13,027    
Accumulated Depreciation 5,700     5,700    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 13,027          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 5,700          
United Dominion Reality L.P. | Western Region | MONTEREY PENINSULA, CA            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       16,938    
Initial Costs, Buildings and Improvements       68,384    
Total Initial Acquisition Costs       85,322    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       79,626    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       27,741    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       137,207    
Total Carrying Value 164,948     164,948    
Accumulated Depreciation 73,729     73,729    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 164,948          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 73,729          
United Dominion Reality L.P. | Western Region | Verano at Rancho Cucamonga Town Square            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       55,262    
Initial Costs, Land and Land Improvements       13,557    
Initial Costs, Buildings and Improvements       3,645    
Total Initial Acquisition Costs       17,202    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       53,949    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       23,255    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       47,896    
Total Carrying Value 71,151     71,151    
Accumulated Depreciation 34,875     34,875    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 71,151          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 34,875          
United Dominion Reality L.P. | Western Region | Tualatin Heights            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       3,273    
Initial Costs, Buildings and Improvements       9,134    
Total Initial Acquisition Costs       12,407    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,745    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       3,841    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       15,311    
Total Carrying Value 19,152     19,152    
Accumulated Depreciation 10,231     10,231    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 19,152          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 10,231          
United Dominion Reality L.P. | Western Region | Hunt Club            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       6,014    
Initial Costs, Buildings and Improvements       14,870    
Total Initial Acquisition Costs       20,884    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,866    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       6,395    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       21,355    
Total Carrying Value 27,750     27,750    
Accumulated Depreciation 14,364     14,364    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 27,750          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 14,364          
United Dominion Reality L.P. | Western Region | PORTLAND, OR            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       9,287    
Initial Costs, Buildings and Improvements       24,004    
Total Initial Acquisition Costs       33,291    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       13,611    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       10,236    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       36,666    
Total Carrying Value 46,902     46,902    
Accumulated Depreciation 24,595     24,595    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 46,902          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 24,595          
United Dominion Reality L.P. | Mid Atlantic Region            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       74,738    
Initial Costs, Land and Land Improvements       83,349    
Initial Costs, Buildings and Improvements       423,244    
Total Initial Acquisition Costs       506,593    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       170,422    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       95,280    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       581,670    
Total Carrying Value 676,950     676,950    
Accumulated Depreciation 208,179     208,179    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 676,950          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 208,179          
United Dominion Reality L.P. | Mid Atlantic Region | Ridgewood            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       5,612    
Initial Costs, Buildings and Improvements       20,086    
Total Initial Acquisition Costs       25,698    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       8,522    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       6,014    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       28,206    
Total Carrying Value 34,220     34,220    
Accumulated Depreciation 20,340     20,340    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 34,220          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 20,340          
United Dominion Reality L.P. | Mid Atlantic Region | Wellington Place at Olde Town            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       32,037    
Initial Costs, Land and Land Improvements       13,753    
Initial Costs, Buildings and Improvements       36,059    
Total Initial Acquisition Costs       49,812    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       17,416    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       14,740    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       52,488    
Total Carrying Value 67,228     67,228    
Accumulated Depreciation 35,000     35,000    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 67,228          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 35,000          
United Dominion Reality L.P. | Mid Atlantic Region | Andover House            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       14,357    
Initial Costs, Buildings and Improvements       51,577    
Total Initial Acquisition Costs       65,934    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       3,769    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       14,379    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       55,324    
Total Carrying Value 69,703     69,703    
Accumulated Depreciation 27,837     27,837    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 69,703          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 27,837          
United Dominion Reality L.P. | Mid Atlantic Region | Sullivan Place            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       1,137    
Initial Costs, Buildings and Improvements       103,676    
Total Initial Acquisition Costs       104,813    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       7,066    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       1,364    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       110,450    
Total Carrying Value 111,814     111,814    
Accumulated Depreciation 51,578     51,578    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 111,814          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 51,578          
United Dominion Reality L.P. | Mid Atlantic Region | Courts at Huntington Station [Member]            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       27,749    
Initial Costs, Buildings and Improvements       111,878    
Total Initial Acquisition Costs       139,627    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       78    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       27,749    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       111,956    
Total Carrying Value 139,705     139,705    
Accumulated Depreciation 1,682     1,682    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 139,705          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 1,682          
United Dominion Reality L.P. | Mid Atlantic Region | METROPOLITAN DC            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       32,037    
Initial Costs, Land and Land Improvements       62,905    
Initial Costs, Buildings and Improvements       336,062    
Total Initial Acquisition Costs       398,967    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       150,208    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       73,707    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       475,403    
Total Carrying Value 549,110     549,110    
Accumulated Depreciation 146,351     146,351    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 549,110          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 146,351          
United Dominion Reality L.P. | Mid Atlantic Region | Lakeside Mill            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       12,569    
Initial Costs, Land and Land Improvements       2,666    
Initial Costs, Buildings and Improvements       10,109    
Total Initial Acquisition Costs       12,775    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       5,038    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       2,997    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       14,816    
Total Carrying Value 17,813     17,813    
Accumulated Depreciation 11,336     11,336    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 17,813          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 11,336          
United Dominion Reality L.P. | Mid Atlantic Region | Calvert’s Walk            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       4,408    
Initial Costs, Buildings and Improvements       24,692    
Total Initial Acquisition Costs       29,100    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       7,396    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       4,817    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       31,679    
Total Carrying Value 36,496     36,496    
Accumulated Depreciation 20,827     20,827    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 36,496          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 20,827          
United Dominion Reality L.P. | Mid Atlantic Region | Liriope Apartments            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       1,620    
Initial Costs, Buildings and Improvements       6,791    
Total Initial Acquisition Costs       8,411    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       1,374    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       1,653    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       8,132    
Total Carrying Value 9,785     9,785    
Accumulated Depreciation 5,352     5,352    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 9,785          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 5,352          
United Dominion Reality L.P. | Mid Atlantic Region | 20 Lambourne            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       30,132    
Initial Costs, Land and Land Improvements       11,750    
Initial Costs, Buildings and Improvements       45,590    
Total Initial Acquisition Costs       57,340    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,406    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       12,106    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       51,640    
Total Carrying Value 63,746     63,746    
Accumulated Depreciation 24,313     24,313    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 63,746          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 24,313          
United Dominion Reality L.P. | Mid Atlantic Region | BALTIMORE, MD            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       42,701    
Initial Costs, Land and Land Improvements       20,444    
Initial Costs, Buildings and Improvements       87,182    
Total Initial Acquisition Costs       107,626    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       20,214    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       21,573    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       106,267    
Total Carrying Value 127,840     127,840    
Accumulated Depreciation 61,828     61,828    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 127,840          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 61,828          
United Dominion Reality L.P. | Mid Atlantic Region | DelRey Tower [Member]            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       297    
Initial Costs, Buildings and Improvements       12,786    
Total Initial Acquisition Costs       13,083    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       113,357    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       9,461    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       116,979    
Total Carrying Value 126,440     126,440    
Accumulated Depreciation 9,914     9,914    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 126,440          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 9,914          
United Dominion Reality L.P. | Southeastern Region            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       39,179    
Initial Costs, Land and Land Improvements       45,330    
Initial Costs, Buildings and Improvements       163,328    
Total Initial Acquisition Costs       208,658    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       113,129    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       54,064    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       267,723    
Total Carrying Value 321,787     321,787    
Accumulated Depreciation 180,879     180,879    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 321,787          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 180,879          
United Dominion Reality L.P. | Southeastern Region | Inlet Bay            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       7,702    
Initial Costs, Buildings and Improvements       23,150    
Total Initial Acquisition Costs       30,852    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       15,659    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       9,304    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       37,207    
Total Carrying Value 46,511     46,511    
Accumulated Depreciation 27,055     27,055    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 46,511          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 27,055          
United Dominion Reality L.P. | Southeastern Region | MacAlpine Place            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       10,869    
Initial Costs, Buildings and Improvements       36,858    
Total Initial Acquisition Costs       47,727    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       7,862    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       11,545    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       44,044    
Total Carrying Value 55,589     55,589    
Accumulated Depreciation 28,780     28,780    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 55,589          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 28,780          
United Dominion Reality L.P. | Southeastern Region | TAMPA, FL            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       18,571    
Initial Costs, Buildings and Improvements       60,008    
Total Initial Acquisition Costs       78,579    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       23,521    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       20,849    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       81,251    
Total Carrying Value 102,100     102,100    
Accumulated Depreciation 55,835     55,835    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 102,100          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 55,835          
United Dominion Reality L.P. | Southeastern Region | Legacy Hill            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       1,148    
Initial Costs, Buildings and Improvements       5,867    
Total Initial Acquisition Costs       7,015    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       8,807    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       1,764    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       14,058    
Total Carrying Value 15,822     15,822    
Accumulated Depreciation 11,246     11,246    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 15,822          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 11,246          
United Dominion Reality L.P. | Southeastern Region | Hickory Run            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       1,469    
Initial Costs, Buildings and Improvements       11,584    
Total Initial Acquisition Costs       13,053    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       10,459    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       2,155    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       21,357    
Total Carrying Value 23,512     23,512    
Accumulated Depreciation 14,244     14,244    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 23,512          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 14,244          
United Dominion Reality L.P. | Southeastern Region | Carrington Hills            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       2,117    
Initial Costs, Buildings and Improvements       0    
Total Initial Acquisition Costs       2,117    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       34,535    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       4,506    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       32,146    
Total Carrying Value 36,652     36,652    
Accumulated Depreciation 21,305     21,305    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 36,652          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 21,305          
United Dominion Reality L.P. | Southeastern Region | Brookridge            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       708    
Initial Costs, Buildings and Improvements       5,461    
Total Initial Acquisition Costs       6,169    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       4,830    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       1,162    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       9,837    
Total Carrying Value 10,999     10,999    
Accumulated Depreciation 7,007     7,007    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 10,999          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 7,007          
United Dominion Reality L.P. | Southeastern Region | Breckenridge            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       766    
Initial Costs, Buildings and Improvements       7,714    
Total Initial Acquisition Costs       8,480    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       4,646    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       1,285    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       11,841    
Total Carrying Value 13,126     13,126    
Accumulated Depreciation 8,155     8,155    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 13,126          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 8,155          
United Dominion Reality L.P. | Southeastern Region | Polo Park            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       4,583    
Initial Costs, Buildings and Improvements       16,293    
Total Initial Acquisition Costs       20,876    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       16,508    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       5,741    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       31,643    
Total Carrying Value 37,384     37,384    
Accumulated Depreciation 22,411     22,411    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 37,384          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 22,411          
United Dominion Reality L.P. | Southeastern Region | NASHVILLE, TN            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       10,791    
Initial Costs, Buildings and Improvements       46,919    
Total Initial Acquisition Costs       57,710    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       79,785    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       16,613    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       120,882    
Total Carrying Value 137,495     137,495    
Accumulated Depreciation 84,368     84,368    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 137,495          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 84,368          
United Dominion Reality L.P. | Southeastern Region | The Reserve and Park at Riverbridge            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       39,179    
Initial Costs, Land and Land Improvements       15,968    
Initial Costs, Buildings and Improvements       56,401    
Total Initial Acquisition Costs       72,369    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       9,823    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       16,602    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       65,590    
Total Carrying Value 82,192     82,192    
Accumulated Depreciation 40,676     40,676    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 82,192          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 40,676          
United Dominion Reality L.P. | Southeastern Region | OTHER FLORIDA            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       39,179    
Initial Costs, Land and Land Improvements       15,968    
Initial Costs, Buildings and Improvements       56,401    
Total Initial Acquisition Costs       72,369    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       9,823    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       16,602    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       65,590    
Total Carrying Value 82,192     82,192    
Accumulated Depreciation 40,676     40,676    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 82,192          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 40,676          
United Dominion Reality L.P. | Northeast Region            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       110,030    
Initial Costs, Buildings and Improvements       536,413    
Total Initial Acquisition Costs       646,443    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       23,199    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       110,383    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       559,259    
Total Carrying Value 669,642     669,642    
Accumulated Depreciation 142,858     142,858    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 669,642          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 142,858          
United Dominion Reality L.P. | Northeast Region | 14 North            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       10,961    
Initial Costs, Buildings and Improvements       51,175    
Total Initial Acquisition Costs       62,136    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,359    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       11,077    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       57,418    
Total Carrying Value 68,495     68,495    
Accumulated Depreciation 16,632     16,632    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 68,495          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 16,632          
United Dominion Reality L.P. | Northeast Region | BOSTON, MA            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       10,961    
Initial Costs, Buildings and Improvements       51,175    
Total Initial Acquisition Costs       62,136    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       6,359    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       11,077    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       57,418    
Total Carrying Value 68,495     68,495    
Accumulated Depreciation 16,632     16,632    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 68,495          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 16,632          
United Dominion Reality L.P. | Northeast Region | 10 Hanover Square            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       41,432    
Initial Costs, Buildings and Improvements       218,983    
Total Initial Acquisition Costs       260,415    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       9,730    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       41,496    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       228,649    
Total Carrying Value 270,145     270,145    
Accumulated Depreciation 54,457     54,457    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 270,145          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 54,457          
United Dominion Reality L.P. | Northeast Region | 95 Wall Street            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       57,637    
Initial Costs, Buildings and Improvements       266,255    
Total Initial Acquisition Costs       323,892    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       7,110    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       57,810    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       273,192    
Total Carrying Value 331,002     331,002    
Accumulated Depreciation 71,769     71,769    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 331,002          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 71,769          
United Dominion Reality L.P. | Northeast Region | NEW YORK, NY            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       0    
Initial Costs, Land and Land Improvements       99,069    
Initial Costs, Buildings and Improvements       485,238    
Total Initial Acquisition Costs       584,307    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       16,840    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       99,306    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       501,841    
Total Carrying Value 601,147     601,147    
Accumulated Depreciation 126,226     126,226    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 601,147          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 126,226          
United Dominion Reality L.P. | Total Operating Properties [Member]            
Real Estate and Accumulated Depreciation [Line Items]            
Encumbrances       478,163    
Initial Costs, Land and Land Improvements       747,171    
Initial Costs, Buildings and Improvements       2,082,113    
Total Initial Acquisition Costs       2,829,284    
Costs of Improvements Capitalized Subsequent to Acquisition Costs       805,694    
Gross Amount at Which Carried at Close of Period, Land and Land Improvements       831,920    
Gross Amount at Which Carried at Close of Period, Buildings & Buildings Improvements       2,790,464    
Total Carrying Value 3,622,384     3,622,384    
Accumulated Depreciation 1,278,575     1,278,575    
Real Estate Owned, Gross [Roll Forward]            
Balance at end of the year 3,622,384          
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Balance at end of year 1,278,575          
Corporate Joint Venture [Member]            
Real Estate Owned, Gross [Roll Forward]            
Real estate acquired 0 0 129,437      
Retirement of fully depreciated assets 0 (112,344) (356,303)      
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Accumulated depreciation on retirements of fully depreciated asset $ 0 $ (4,228) $ (20,662)      
UDR Lighthouse DownREIT L.P. [Member] | United Dominion Reality L.P.            
Real Estate Owned, Gross [Roll Forward]            
Real Estate Investment Property, at Cost       (628,479) 0 0
Real Estate Owned, Accumulated Depreciation [Roll Forward]            
Real Estate Owned, Accumulated Depreciation       $ (223,363) $ 0 $ 0
[1] Includes unallocated accruals and capital expenditures.The aggregate cost for federal income tax purposes was approximately $8.3 billion at December 31, 2015. The estimated depreciable lives for all buildings in the latest Consolidated Statements of Operations are 35 to 55 years.
[2] Includes unallocated accruals and capital expenditures.The aggregate cost for federal income tax purpose was approximately $3.0 billion at December 31, 2015.