Investments in Real Estate Entities (Details 2) (USD $)	12 Months Ended				12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Nov. 30, 2012 Archstone Enterprise LP	Dec. 31, 2012 Avalon Del Rey, LLC	Dec. 31, 2011 Avalon Del Rey, LLC	Dec. 31, 2010 Avalon Del Rey, LLC	Dec. 31, 2012 CVP I, LLC	Dec. 31, 2011 CVP I, LLC	Dec. 31, 2010 CVP I, LLC	Dec. 31, 2012 MVP I, LLC	Dec. 31, 2011 MVP I, LLC	Dec. 31, 2010 MVP I, LLC	Dec. 31, 2011 AvalonBay Value Added Fund, L.P.	Dec. 31, 2010 AvalonBay Value Added Fund, L.P.	Dec. 31, 2012 AvalonBay Value Added Fund II, L.P	Dec. 31, 2011 AvalonBay Value Added Fund II, L.P	Dec. 31, 2010 AvalonBay Value Added Fund II, L.P	Dec. 31, 2012 Juanita Village
Assets:
Real estate, net	$ 1,337,084,000	$ 1,583,397,000
Other assets	73,252,000	70,233,000
Total assets	1,410,336,000	1,653,630,000
Liabilities and partners' capital:
Mortgage notes payable and credit facility	943,259,000	1,074,429,000
Other liabilities	20,405,000	27,335,000
Partners' capital	446,672,000	551,866,000
Total liabilities and partners' capital	1,410,336,000	1,653,630,000
Combined summary of the operating results of the accounted for using the equity method
Rental and other income	172,076,000	160,066,000	114,755,000
Operating and other expenses	(73,955,000)	(71,926,000)	(56,322,000)
Gain on sale of communities	106,195,000	22,246,000			44,700									3,063,000
Interest expense, net	(53,904,000)	(50,530,000)	(40,050,000)
Depreciation expense	(47,748,000)	(47,920,000)	(36,631,000)
Net income	102,664,000	11,936,000	(18,248,000)
Costs in excess of equity in underlying net assets of the respective investments					7,342,000	9,167,000
Summary of the Company's equity in income of unconsolidated entities
Equity in income of unconsolidated entities	20,914,000	5,120,000	762,000		4,000,000	102,000	1,000	5,394,000	4,493,000	4,368,000	493,000	(626,000)	(881,000)	2,204,000	(1,653,000)	2,130,000	(1,053,000)	(1,073,000)
Equity in income of unconsolidated entities relating to the Company's recognition of promoted interest								2,865,000	2,815,000	2,839,000									1,856,000
Gain on sale of assets	106,195,000	22,246,000			44,700									3,063,000
Transaction costs				$ 9,593,000