Mortgage-Backed Securities - Summary of Credit Loss Allowance (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Beginning allowance for credit losses	$ 10,251	$ 453	$ 7,188	$ 213
Additions to the allowance for credit losses on securities for which credit losses were not previously recorded	502	1,253	1,099	1,592
Allowance on purchased financial assets with credit deterioration	0	0	0	0
Reductions for the securities sold during the period	0	0	0	0
Increase/(decrease) on securities with an allowance in the prior period	3,459	3,062	7,551	3,021
Write-offs charged against the allowance	(1,228)	(18)	(2,858)	(76)
Recoveries of amounts previously written off	29	140	33	140
Ending allowance for credit losses	$ 13,013	$ 4,890	$ 13,013	$ 4,890