Loans and Preferred Equity Held for Investment, net and Loans Held for Sale - Nonaccrual and Past Due Loans (Details) $ in Thousands		Aug. 07, 2020 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($) loan
Financing Receivable, Past Due [Line Items]
Loans and preferred equity held for investment, net	[1]		$ 2,242,574	$ 2,576,332
Midwest hospitality | Subsequent event
Financing Receivable, Past Due [Line Items]
Bridge loan		$ 19,500
Commercial mortgage
Financing Receivable, Past Due [Line Items]
Loans and preferred equity held for investment, net			2,295,095	2,848,956
Commercial mortgage | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans and preferred equity held for investment, net			2,265,249	2,558,505
Commercial mortgage | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans and preferred equity held for investment, net			0	32,322
Commercial mortgage | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans and preferred equity held for investment, net			0	0
Commercial mortgage | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Loans and preferred equity held for investment, net			$ 29,846	$ 258,129
Hospitality | Core | Midwest hospitality
Financing Receivable, Past Due [Line Items]
Number of loans, non-accrual status | loan				1
NY hospitality loans
Financing Receivable, Past Due [Line Items]
Number of loans, non-accrual status | loan				4
Commercial mortgage, hospitality loan | 90 Days or More Past Due | First mortgage loans
Financing Receivable, Past Due [Line Items]
Loans and preferred equity held for investment, net				$ 258,100

[1] Net of $52.5 million and $272.6 million of allowance for loan losses at June 30, 2020 and December 31, 2019, respectively. See Note 3, “Loans and Preferred Equity Held for Investments, net and Loans Held for Sale” for further details.