Impairment Charges and Reserves - Impairment Charges on Assets or Investments (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Impairment Charges And Impairment Of Joint Venture Investments [Abstract]
Assets marketed for sale	$ 600	$ 5,800	$ 58,200
Assets included in the spin-off of RVI	0	62,600	267,200
Reserve of preferred equity interests	15,544	11,422	61,000
Total impairment charges	18,900	80,700	401,500
Undeveloped Land [Member]
Impairment Charges And Impairment Of Joint Venture Investments [Abstract]
Assets marketed for sale	$ 2,800	$ 900	$ 15,100

The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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Period Type:	duration