Fair Value - Narrative (Details) - Discounted cash flow method - Real estate investment - Nonrecurring	Sep. 30, 2020
Minimum | Terminal capitalization rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Measurement input (percentage)	0.0625
Minimum | Discount rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Measurement input (percentage)	0.070
Maximum | Terminal capitalization rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Measurement input (percentage)	0.0775
Maximum | Discount rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Measurement input (percentage)	0.0775