Securitization Transactions (Schedule of Residential Loan Securitizations) (Details) - Non-QM loan securitization - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2018
November 2017 [Member]
Securitization Transactions [Line Items]
Total Face Amount of Certificates Issued		$ 141,233
Economic interest retained		5.10%
Purchase of certificates		$ 700
November 2018 [Member]
Securitization Transactions [Line Items]
Total Face Amount of Certificates Issued		$ 232,518
Economic interest retained		5.70%
Purchase of certificates		$ 1,300
June 2019 [Member]
Securitization Transactions [Line Items]
Total Face Amount of Certificates Issued	$ 226,913
Economic interest retained	6.10%
Purchase of certificates	$ 1,200
November 2019 [Member]
Securitization Transactions [Line Items]
Total Face Amount of Certificates Issued	$ 267,255
Economic interest retained	6.40%
Purchase of certificates	$ 1,700
June 2020 [Member]
Securitization Transactions [Line Items]
Total Face Amount of Certificates Issued	259,273
Purchase of certificates	1,900
November 2020
Securitization Transactions [Line Items]
Total Face Amount of Certificates Issued	219,732
Purchase of certificates	1,400
The Company [Member] | November 2017 [Member]
Securitization Transactions [Line Items]
Principal Balance of Loans Transferred to the Depositor		141,233
The Company [Member] | November 2018 [Member]
Securitization Transactions [Line Items]
Principal Balance of Loans Transferred to the Depositor		$ 232,518
The Company [Member] | June 2019 [Member]
Securitization Transactions [Line Items]
Principal Balance of Loans Transferred to the Depositor	226,913
The Company [Member] | November 2019 [Member]
Securitization Transactions [Line Items]
Principal Balance of Loans Transferred to the Depositor	267,255
The Company [Member] | June 2020 [Member]
Securitization Transactions [Line Items]
Principal Balance of Loans Transferred to the Depositor	259,273
The Company [Member] | November 2020
Securitization Transactions [Line Items]
Principal Balance of Loans Transferred to the Depositor	$ 219,732
Retained, non-risk retention [Member] | June 2020 [Member]
Securitization Transactions [Line Items]
Economic interest retained	3.50%
Retained, risk retention rules [Member] | June 2020 [Member]
Securitization Transactions [Line Items]
Economic interest retained	8.00%
Retained, risk retention rules [Member] | November 2020
Securitization Transactions [Line Items]
Economic interest retained	7.60%