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Consolidation and Basis of Presentation (UNITED DOMINION REALTY, L.P.) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2015 Communities Apartment_Homes Markets shares	Jun. 30, 2014	Jun. 30, 2015 Communities Apartment_Homes Markets shares	Jun. 30, 2014	Dec. 31, 2014 shares
Entity Information [Line Items]
Number of Real Estate Properties | Communities	136		136
Number of apartments owned (in apartments homes) | Apartment_Homes	39,404		39,404
Operating Partnership outstanding units	183,278,698		183,278,698
Percentage of units outstanding in Heritage OP	4.90%		4.90%
Limited Partners [Member]
Entity Information [Line Items]
Operating Partnership outstanding units	9,062,689		9,062,689
United Dominion Reality L.P. [Member]
Entity Information [Line Items]
Rental revenues percent of General Partner's consolidated rental revenues	53.00%	52.00%	53.00%	52.40%
Number of Real Estate Properties | Communities	67		67
Number of markets operating within (in markets) | Markets	17		17
Number of apartments owned (in apartments homes) | Apartment_Homes	20,569		20,569
OP units outstanding related to general partner	110,883		110,883		110,883
OP units outstanding related to limited partner	183,167,815		183,167,815		183,167,815
General Partner [Member]
Entity Information [Line Items]
Operating Partnership outstanding units	174,216,009		174,216,009
Non-affiliated Partners [Member]
Entity Information [Line Items]
OP units outstanding related to limited partner	9,062,689		9,062,689		9,165,473
Percentage of units outstanding in Heritage OP	4.90%		4.90%		5.00%

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