Short-Term Debt - Mortgage Loans Sold Under Agreement to Repurchase by Counterparty (Details) - Loan Repo Facility $ in Thousands	Jun. 30, 2022 USD ($)
Credit Suisse First Boston Mortgage Capital LLC Tranche Two
Mortgage loans sold under agreement to repurchase
Amount at risk	$ 3,085,625
Credit Suisse First Boston Mortgage Capital LLC Tranche One
Mortgage loans sold under agreement to repurchase
Amount at risk	58,007
Bank of America, N.A.
Mortgage loans sold under agreement to repurchase
Amount at risk	82,621
JP Morgan Chase Bank
Mortgage loans sold under agreement to repurchase
Amount at risk	75,401
JP Morgan
Mortgage loans sold under agreement to repurchase
Amount at risk	13,596
BNP Paribas
Mortgage loans sold under agreement to repurchase
Amount at risk	7,534
Barclays
Mortgage loans sold under agreement to repurchase
Amount at risk	19,202
Goldman Sachs
Mortgage loans sold under agreement to repurchase
Amount at risk	16,177
Citibank, N.A.
Mortgage loans sold under agreement to repurchase
Amount at risk	12,895
Morgan Stanley Bank, N.A.
Mortgage loans sold under agreement to repurchase
Amount at risk	4,359
Royal Bank of Canada
Mortgage loans sold under agreement to repurchase
Amount at risk	88,969
Wells Fargo Bank, N.A.
Mortgage loans sold under agreement to repurchase
Amount at risk	$ 18,324