Impairment Charges and Reserves - Summary of Significant Unobservable Inputs (Detail) - Fair Value Measurements [Member] $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred equity interests, Fair Value	$ 94.2
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred equity interests, Fair Value	94.2
Preferred Equity Interests [Member] | Level 3 [Member] | Discounted Cash Flow [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred equity interests, Fair Value	$ 94.2
Preferred Equity Interests [Member] | Level 3 [Member] | Discounted Cash Flow [Member] | Discount Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable inputs rate	7.90%
Preferred Equity Interests [Member] | Level 3 [Member] | Discounted Cash Flow [Member] | Terminal Capitalization Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable inputs rate	8.20%
Preferred Equity Interests [Member] | Level 3 [Member] | Discounted Cash Flow [Member] | NOI Growth Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable inputs rate	0.00%
Unobservable inputs rate	0.00%
Preferred Equity Interests [Member] | Level 3 [Member] | Discounted Cash Flow [Member] | Minimum [Member] | Discount Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable inputs rate	6.60%
Preferred Equity Interests [Member] | Level 3 [Member] | Discounted Cash Flow [Member] | Minimum [Member] | Terminal Capitalization Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable inputs rate	6.60%
Preferred Equity Interests [Member] | Level 3 [Member] | Discounted Cash Flow [Member] | Maximum [Member] | Discount Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable inputs rate	10.60%
Preferred Equity Interests [Member] | Level 3 [Member] | Discounted Cash Flow [Member] | Maximum [Member] | Terminal Capitalization Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable inputs rate	10.50%