Investments in and Advances to Joint Ventures - Condensed Combined Financial Information of Company's Unconsolidated Joint Venture Investments (Parenthetical) (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule Of Equity Method Investments [Line Items]
Redeemable preferred equity, net	$ 204,078	$ 277,776
PIK [Member]
Schedule Of Equity Method Investments [Line Items]
Redeemable preferred equity, net	$ 10,800	$ 6,300