Real Estate Investments Preferred Equity Investments and Real Estate Under Development (Details) $ in Thousands		1 Months Ended			12 Months Ended
	Oct. 31, 2014 USD ($)	Aug. 31, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($) unit joint_venture project	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Schedule of Equity Method Investments [Line Items]
Co-investment		$ 20,400		$ 13,700	$ 1,036,047	$ 1,042,423
Payments to acquire additional investments				1,300
Payments to acquire equity method investments				1,300	127,879	246,006	$ 162,578
Gain on disposal of equity method investment		$ 1,500			$ (31,556)	(13,900)	$ 0
Number of development projects | project					2
Ownership interests, number of active development projects | project					8
Real Estate Under Development Activities [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interests, number of active development projects | joint_venture					6
Real Estate predevelopment projects [Member]
Schedule of Equity Method Investments [Line Items]
Number of units to be developed | unit					2,447
Estimated cost active development projects					$ 1,400,000
Active development projects estimated costs to be expended					787,000
Remaining estimated cost to be contributed by Company					542,000
Total preferred interest investments [Member]
Schedule of Equity Method Investments [Line Items]
Co-investment					$ 106,312	$ 108,691
Preferred interest in a related party limited liability company that owns Madison Park at Anaheim with a preferred return of 9% [Member]
Schedule of Equity Method Investments [Line Items]
Co-investment				$ 13,700
Cumulative dividend rate (in hundredths)				9.00%
Greentree Apartments [Member] | Limited Liability Company [Member]
Schedule of Equity Method Investments [Line Items]
Cumulative dividend rate (in hundredths)			9.50%
Payments to acquire equity method investments			$ 10,000
Sterling Cove [Member] | Limited Liability Company [Member]
Schedule of Equity Method Investments [Line Items]
Cumulative dividend rate (in hundredths)			9.50%
Payments to acquire equity method investments			$ 5,000
Alta Vista Apartments [Member] | Limited Liability Company [Member]
Schedule of Equity Method Investments [Line Items]
Cumulative dividend rate (in hundredths)		9.50%
Payments to acquire equity method investments		$ 5,000
Equity Method Investments [Member]
Schedule of Equity Method Investments [Line Items]
Redemption of preferred equity investments	$ 101,000
Gain from redemption penalties due to early redemption of preferred equity investments	$ 5,300