Investments in and Advances to Joint Ventures - Condensed Combined Financial Information of Company's Unconsolidated Joint Venture Investments (Parenthetical) (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Schedule Of Equity Method Investments [Line Items]
Preferred investment interest valuation allowance	$ 73.5	$ 72.4
PIK [Member]
Schedule Of Equity Method Investments [Line Items]
Redeemable preferred equity, net	$ 13.5	$ 12.2