Distressed and Other Residential Mortgage Loans, Net - Delinquencies in Portfolio of Residential Mortgage Loans Held in Securitization Trusts (Details) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019 USD ($) loan	Dec. 31, 2018 USD ($) loan
Financing Receivable, Past Due [Line Items]
Real estate owned through foreclosure, Number of Delinquent Loans | loan	1
Real estate owned through foreclosure, Total Unpaid Principal | $	$ 360
Real estate owned through foreclosure, % of Loan Portfolio	0.69%
30-60
Financing Receivable, Past Due [Line Items]
Number of Delinquent Loans | loan	1
Total Unpaid Principal | $	$ 264
% of Loan Portfolio	0.50%
90
Financing Receivable, Past Due [Line Items]
Number of Delinquent Loans | loan	18	19
Total Unpaid Principal | $	$ 10,384	$ 10,926
% of Loan Portfolio	19.85%	18.16%