Unconsolidated Entities - Summary of Investments in and Advances to our Unconsolidated Entities (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule Of Equity Method Investments [Line Items]
Investments in and advances to unconsolidated entities	$ 5,613,060	$ 5,745,294
Unconsolidated Co-Investment Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Investments in and advances to unconsolidated entities	5,272,073	5,407,838
Other Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Investments in and advances to unconsolidated entities	$ 340,987	$ 337,456