Investments in Agency MBS - Additional Information About Gains and Losses Recognized with Respect to Investments in Agency MBS (Details) - Agency MBS - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Net gains (losses) recognized in earnings for:    
MBS still held at period end $ (15,116) $ 8,682
MBS sold during the period (13,249) 22,344
Total $ (28,365) $ 31,026