Mortgage-Backed Securities - Percentage of Non-Agency RMBS By Year Originated (Details) - Non-Agency RMBS	Mar. 31, 2022	Dec. 31, 2021
Origination Year as a Percentage of Outstanding Principal Balance:
2003 (and prior)	1.40%	1.40%
2004	1.20%	1.20%
2005	9.50%	8.60%
2006	45.40%	53.70%
2007	30.90%	25.30%
2008 and later	11.60%	9.80%
Total	100.00%	100.00%