Financing - Summary of repurchase agreements (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	$ 3,883,539	$ 2,776,958
Securitized residential mortgage loans
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	3,262,352	999,215
Residential Mortgage Loans
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	360,241	1,286,287
Residential Mortgage Loans | Securitized residential mortgage loans
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	232,088	71,308
Residential Mortgage Loans | Within 30 Days
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	0
Residential Mortgage Loans | Within 30 Days | Securitized residential mortgage loans
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	144,488
Residential Mortgage Loans | Over 30 Days to 3 Months
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	162,508
Residential Mortgage Loans | Over 30 Days to 3 Months | Securitized residential mortgage loans
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	87,600
Residential Mortgage Loans | Over 3 Months to 12 Months
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	165,979
Residential Mortgage Loans | Over 3 Months to 12 Months | Securitized residential mortgage loans
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	0
Residential Mortgage Loans | Over 12 Months
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	31,754
Residential Mortgage Loans | Over 12 Months | Securitized residential mortgage loans
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	0
Non-Agency RMBS
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	14,695	10,213
Non-Agency RMBS | Within 30 Days
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	10,859
Non-Agency RMBS | Over 30 Days to 3 Months
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	3,836
Non-Agency RMBS | Over 3 Months to 12 Months
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	0
Non-Agency RMBS | Over 12 Months
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	0
Agency RMBS
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	14,163	409,935
Agency RMBS | Within 30 Days
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	14,163
Agency RMBS | Over 30 Days to 3 Months
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	0
Agency RMBS | Over 3 Months to 12 Months
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	0
Agency RMBS | Over 12 Months
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	0
Total Financing Arrangements
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	621,187	$ 1,777,743
Total Financing Arrangements | Within 30 Days
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	169,510
Total Financing Arrangements | Over 30 Days to 3 Months
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	253,944
Total Financing Arrangements | Over 3 Months to 12 Months
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	165,979
Total Financing Arrangements | Over 12 Months
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value	$ 31,754