Segment Reporting Assets and Liabilities by Segment (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Total Assets	$ 14,302,865		$ 14,085,886
Liabilities	12,958,208		12,865,000
Total Equity	1,344,657	$ 1,374,763	1,220,886	$ 1,234,455	$ 1,322,938	$ 1,323,556
Investment Portfolio Segment
Segment Reporting Information [Line Items]
Total Assets	5,475,115		5,635,657
Liabilities	4,239,262		4,499,669
Total Equity	1,235,853		1,135,988
Longbridge Segment
Segment Reporting Information [Line Items]
Total Assets	8,632,657		8,227,509
Liabilities	8,439,949		8,092,313
Total Equity	192,708		135,196
Corporate and Other
Segment Reporting Information [Line Items]
Total Assets	195,093		222,720
Liabilities	278,997		273,018
Total Equity	$ (83,904)		$ (50,298)