Fair Value - Narrative (Details) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment loss	$ 91,400	$ 10,100
Nonrecurring | Level 3 | Operating Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment loss	90,715		$ 27,021
Nonrecurring | Level 3 | Assets Held-For-Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment loss	$ 722		$ 533
Discounted cash flow method | Minimum | Real estate investment | Terminal capitalization rate | Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Measurement input (percentage)	0.0625
Discounted cash flow method | Minimum | Real estate investment | Discount rate | Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Measurement input (percentage)	0.070
Discounted cash flow method | Maximum | Real estate investment | Terminal capitalization rate | Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Measurement input (percentage)	0.0775
Discounted cash flow method | Maximum | Real estate investment | Discount rate | Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Measurement input (percentage)	0.0775