Investments in and Advances to Joint Ventures - Condensed Combined Statements of Operations of Unconsolidated Joint Venture Investments (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) Property
Schedule Of Equity Method Investments [Line Items]
Company's proportionate share of the impairment charges	$ 2,700,000	$ 10,500,000	$ 4,400,000
Company's share of aggregate impairment charges reclassified to discontinued operations			$ 800,000
Number of properties sold under discontinued operations | Property			35
Investment basis value for which no income loss recognized	$ 0
Unconsolidated Joint Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Impairment charges reclassified to discontinued operations related to asset sales			$ 11,100,000
Number of properties sold under discontinued operations | Property			37