Secured Financing Agreements - Schedule of Secured Financing Agreements (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Assets Sold under Agreements to Repurchase [Line Items]
Secured financing agreements outstanding principal secured by:	$ 2,384,678	$ 2,432,115
Repurchase Agreements
Assets Sold under Agreements to Repurchase [Line Items]
Secured financing agreements outstanding principal secured by:	2,403,678	2,444,091
Average balance of Secured financing agreements secured by:	2,421,953	2,836,314
Repurchase Agreements | Asset Pledged as Collateral
Assets Sold under Agreements to Repurchase [Line Items]
MBS pledged as collateral at fair value on Secured financing agreements:	3,553,582	3,539,416
Repurchase Agreements | Agency RMBS
Assets Sold under Agreements to Repurchase [Line Items]
Average balance of Secured financing agreements secured by:	0	1,551
Repurchase Agreements | Agency CMBS
Assets Sold under Agreements to Repurchase [Line Items]
Secured financing agreements outstanding principal secured by:	36,434	68,502
Average balance of Secured financing agreements secured by:	$ 44,632	$ 139,746
Average borrowing rate of Secured financing agreements secured by:	5.47%	5.60%
Average remaining maturity of Secured financing agreements secured by:	34 days	32 days
Average original maturity of Secured financing agreements secured by:	45 days	86 days
Repurchase Agreements | Agency CMBS | Asset Pledged as Collateral
Assets Sold under Agreements to Repurchase [Line Items]
MBS pledged as collateral at fair value on Secured financing agreements:	$ 38,644	$ 74,345
Repurchase Agreements | Non-agency MBS and Loans held for investment
Assets Sold under Agreements to Repurchase [Line Items]
Secured financing agreements outstanding principal secured by:	2,367,244	2,375,589
Average balance of Secured financing agreements secured by:	$ 2,377,321	$ 2,695,017
Average borrowing rate of Secured financing agreements secured by:	7.51%	7.56%
Average remaining maturity of Secured financing agreements secured by:	378 days	418 days
Average original maturity of Secured financing agreements secured by:	401 days	445 days
Repurchase Agreements | Non-agency MBS and Loans held for investment | Asset Pledged as Collateral
Assets Sold under Agreements to Repurchase [Line Items]
MBS pledged as collateral at fair value on Secured financing agreements:	$ 3,514,938	$ 3,465,071