Fair Value - Narrative (Details) $ in Thousands	1 Months Ended	3 Months Ended			6 Months Ended		12 Months Ended
	Aug. 07, 2020 USD ($)	Jun. 30, 2020 USD ($) measurement_input loan	Mar. 31, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) measurement_input loan	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) measurement_input
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized (gain) loss on mortgage loans and obligations held in securitization trusts, net		$ 8,975		$ (5,549)	$ 28,427	$ (6,578)
Allowance for loan losses							$ 272,600
Effect of CECL adoption					21,093	0
Provision for loan losses		(51)		110,258	69,881	110,258
Core
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized (gain) loss on mortgage loans and obligations held in securitization trusts, net		8,975		(5,549)	$ 28,427	(6,578)
Number of loans | loan					1
Provision for loan losses		38,000
Core | Subsequent event
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proceeds from sale of receivables	$ 105,200
Core | West Hospitality
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gain (loss) on sales of loans, net		(32,800)
Allowance for loan losses			$ 5,200
Effect of CECL adoption			2,600
Provision for loan losses			$ 2,600
Core | West Hospitality | Subsequent event
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gain (loss) on sales of loans, net	(300)
Proceeds from sale of receivables	$ 105,200
Legacy, Non-Strategic
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment on real estate properties		$ 25,900			$ 25,900
CECL reserve on Loans and preferred equity held for investment, net | Core
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of loans individually evaluated for impairment | loan		2			2
Terminal Capitalization Rate | Minimum | Legacy, Non-Strategic
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Real estate investment property, net, measurement input (in percentage)		0.06			0.06
Terminal Capitalization Rate | Maximum | Legacy, Non-Strategic
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Real estate investment property, net, measurement input (in percentage)		0.16			0.16
Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Provision for loan losses		$ 37,957		0	$ 107,908	0
Nonrecurring | Loans held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Provision for loan losses		32,840		0	69,415	0
Nonrecurring | CECL reserve on Loans and preferred equity held for investment, net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Provision for loan losses		$ 5,117		$ 0	$ 38,493	$ 0
Level 3 | Recurring | Investments in unconsolidated ventures - PE Investments | Discount Rate | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
PE investment, measurement input | measurement_input		0.110			0.110
Level 3 | Recurring | Investments in unconsolidated ventures - PE Investments | Discount Rate | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
PE investment, measurement input | measurement_input		0.120			0.120
Level 3 | Recurring | Mortgage obligations issued by securitization trusts | Measurement Input, Yield | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate | measurement_input		0.142			0.142		0.150
Level 3 | Recurring | Mortgage obligations issued by securitization trusts | Measurement Input, Yield | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate | measurement_input		0.360			0.360		0.161
Level 3 | Recurring | Mortgage obligations issued by securitization trusts | Measurement Input, Expected Term | Weighted average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average expected maturity of CRE securities					5 years 6 months		5 years 4 months 24 days