Mortgage-Backed Securities - Summary of Credit Loss Allowance (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Beginning allowance for credit losses	$ 23,591	$ 13,013	$ 18,560	$ 7,188
Additions to the allowance for credit losses on securities for which credit losses were not previously recorded	6	415	1,595	1,514
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	(1,440)	2,802	1,810	10,355
Write-offs charged against the allowance	(110)	0	(412)	(2,860)
Recoveries of amounts previously written off	1,902	0	2,396	33
Ending allowance for credit losses	$ 23,949	$ 16,230	$ 23,949	$ 16,230