Impairment Charges and Reserves - Impairment Charges and Reserves Measured at Fair Value on Non-Recurring Basis (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-lived assets held and used, Total Impairment Charges	$ 0	$ 5,800	$ 600	$ 5,800
Preferred equity interests, Total Impairment Charges	6,400	$ 2,200	12,106	$ 4,537
Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-lived assets held and used, Fair Value Measurements	5,000		5,000
Preferred equity interests, Fair Value Measurements	158,500		158,500
Long-lived assets held and used, Total Impairment Charges			3,400
Preferred equity interests, Total Impairment Charges			12,100
Fair Value Measurements [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-lived assets held and used, Fair Value Measurements	0		0
Preferred equity interests, Fair Value Measurements	0		0
Fair Value Measurements [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-lived assets held and used, Fair Value Measurements	0		0
Preferred equity interests, Fair Value Measurements	0		0
Fair Value Measurements [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-lived assets held and used, Fair Value Measurements	5,000		5,000
Preferred equity interests, Fair Value Measurements	$ 158,500		$ 158,500