Related Party Transactions (Details) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Mar. 31, 2017 USD ($) unit	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) investment	Dec. 31, 2016 USD ($)	Nov. 30, 2016 USD ($)
Related Party Transaction [Line Items]
Management and other fees from affiliates		$ 3,000	$ 3,300
Development and redevelopment fees		800	1,300
Co-investments	$ 1,071,258	1,071,258			$ 1,161,275
Payments to acquire preferred equity investments		120,816	$ 50,591
Short-term loans outstanding and due from various joint ventures	3,700	3,700			4,700
Notes and other receivables (includes related party receivables of $10.3 million and $11.3 million as of March 31, 2017 and December 31, 2016, respectively)	50,855	50,855			40,970
Limited Liability Company [Member]
Related Party Transaction [Line Items]
Payments to acquire preferred equity investments				$ 20,000
Number of preferred equity method investments acquired during period (in investments) | investment				3
Preferred stock, stated interest percentage (as a percent)				9.50%
Secured Note Receivable, 9.5% Interest Rate, Due October 2019 [Member]
Related Party Transaction [Line Items]
Notes and other receivables (includes related party receivables of $10.3 million and $11.3 million as of March 31, 2017 and December 31, 2016, respectively)	6,594	6,594			6,593
Secured Note Receivable, 9.5% Interest Rate, Due October 2019 [Member] | Marcus and Millichamp Company TMMC Affiliate [Member]
Related Party Transaction [Line Items]
Notes and other receivables (includes related party receivables of $10.3 million and $11.3 million as of March 31, 2017 and December 31, 2016, respectively)	6,600	6,600			$ 6,600	$ 6,600
Membership Interest In Sage At Cupertino [Member]
Related Party Transaction [Line Items]
Co-investments	$ 15,300	15,300
Number of units acquired (in units) | unit	230
Equity method investment, ownership percentage acquired (as a percent)	40.50%
Contract price	$ 90,000
Mortgage encumbrance	$ 52,000	$ 52,000