Investments in and Advances to Joint Ventures - Condensed Combined Financial Information of Company's Unconsolidated Joint Venture Investments (Parenthetical) (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Schedule Of Equity Method Investments [Line Items]
Preferred investment interest valuation allowance	$ 84.5	$ 72.4
PIK [Member]
Schedule Of Equity Method Investments [Line Items]
Redeemable preferred equity, net	$ 16.1	$ 12.2

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