Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net Amount of Assets Presented in the Balance Sheet	$ 4,594	$ 7,102
Net Amount of Liabilities Presented in the Balance Sheet	22,029	22,595
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MBS	5,583,758	3,112,705
Total assets carried at fair value	5,588,352	3,119,807
Total liabilities carried at fair value	22,029	22,595
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MBS	0	0
Total assets carried at fair value	3,946	5,859
Total liabilities carried at fair value	0	0
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MBS	5,583,655	3,112,553
Total assets carried at fair value	5,584,303	3,113,796
Total liabilities carried at fair value	22,029	22,595
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MBS	103	152
Total assets carried at fair value	103	152
Total liabilities carried at fair value	0	0
Fair Value, Measurements, Recurring | Options on U.S. Treasury futures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net Amount of Assets Presented in the Balance Sheet	3,946	5,859
Fair Value, Measurements, Recurring | Options on U.S. Treasury futures | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net Amount of Assets Presented in the Balance Sheet	3,946	5,859
Fair Value, Measurements, Recurring | Options on U.S. Treasury futures | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net Amount of Assets Presented in the Balance Sheet	0	0
Fair Value, Measurements, Recurring | Options on U.S. Treasury futures | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net Amount of Assets Presented in the Balance Sheet	0	0
Fair Value, Measurements, Recurring | TBA securities | Long position
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net Amount of Assets Presented in the Balance Sheet	648	1,243
Net Amount of Liabilities Presented in the Balance Sheet	22,029	22,595
Fair Value, Measurements, Recurring | TBA securities | Level 1 | Long position
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net Amount of Assets Presented in the Balance Sheet	0	0
Net Amount of Liabilities Presented in the Balance Sheet	0	0
Fair Value, Measurements, Recurring | TBA securities | Level 2 | Long position
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net Amount of Assets Presented in the Balance Sheet	648	1,243
Net Amount of Liabilities Presented in the Balance Sheet	22,029	22,595
Fair Value, Measurements, Recurring | TBA securities | Level 3 | Long position
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net Amount of Assets Presented in the Balance Sheet	0	0
Net Amount of Liabilities Presented in the Balance Sheet	$ 0	$ 0