Impairment Charges and Reserves - Impairment Charges and Reserves Measured at Fair Value on Non-Recurring Basis (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-lived assets held and used, Total Impairment Charges	$ 600	$ 0
Preferred equity interests, Total Impairment Charges	1,099	$ 3,961
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	800
Preferred equity interests, Fair Value Measurements	172,000
Long-lived assets held and used, Total Impairment Charges	600
Preferred equity interests, Total Impairment Charges	1,100
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
Preferred equity interests, Fair Value Measurements	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
Preferred equity interests, Fair Value Measurements	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	800
Preferred equity interests, Fair Value Measurements	$ 172,000