Basis of Presentation and Summary of Significant Accounting Policies (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Basis of Presentation and Summary of Significant Accounting Policies
Net real estate	$ 5,391,209,000	$ 5,234,961,000
Non-recourse property debt	4,337,785,000	4,413,083,000
Net below market lease amounts	16,900,000	19,800,000
Accumulated amortization of below market lease values	(35,900,000)	(33,000,000)
Amortization of below market lease values included in rental and other property revenues	(2,900,000)	(3,800,000)	(4,300,000)
Interest costs capitalized	17,600,000	16,600,000	14,000,000
Other direct and indirect costs capitalized	33,200,000	33,700,000	29,000,000
Minimum [Member]
Basis of Presentation and Summary of Significant Accounting Policies
Depreciable life of acquired buildings and improvements	5 years
Average [Member]
Basis of Presentation and Summary of Significant Accounting Policies
Depreciable life of acquired buildings and improvements	15 years
Maximum [Member]
Basis of Presentation and Summary of Significant Accounting Policies
Depreciable life of acquired buildings and improvements	30 years
Building and Building Improvements [Member] | Weighted Average [Member]
Basis of Presentation and Summary of Significant Accounting Policies
Depreciable life of acquired buildings and improvements	30 years
Leases, Acquired-in-Place, Market Adjustment [Member]
Basis of Presentation and Summary of Significant Accounting Policies
Weighted average amortization period	6 years 6 months 15 days
Variable Interest Entity, Primary Beneficiary [Member]
Basis of Presentation and Summary of Significant Accounting Policies
Number of variable interest entities	63
Number of apartment communities	49
Number of homes in apartment communities	7,656
Net real estate	392,245,000	578,421,000
Non-recourse property debt	$ 355,372,000	$ 477,791,000