Short-Term Debt - Mortgage Loans Sold Under Agreement to Repurchase by Counterparty (Details) - Loan Repo Facility $ in Thousands	Mar. 31, 2024 USD ($)
Atlas Securitized Products L.P. & Citibank, N.A. & Goldman Sachs Bank USA
Mortgage loans sold under agreement to repurchase
Amount at risk	$ 4,537,873
Bank of America, N.A.
Mortgage loans sold under agreement to repurchase
Amount at risk	73,125
JP Morgan
Mortgage loans sold under agreement to repurchase
Amount at risk	21,732
BNP Paribas
Mortgage loans sold under agreement to repurchase
Amount at risk	13,954
Atlas Securitized Products, L.P.
Mortgage loans sold under agreement to repurchase
Amount at risk	121,197
Barclays
Mortgage loans sold under agreement to repurchase
Amount at risk	30,560
Goldman Sachs
Mortgage loans sold under agreement to repurchase
Amount at risk	12,362
Citibank, N.A.
Mortgage loans sold under agreement to repurchase
Amount at risk	7,661
Morgan Stanley Bank, N.A.
Mortgage loans sold under agreement to repurchase
Amount at risk	11,023
Royal Bank of Canada
Mortgage loans sold under agreement to repurchase
Amount at risk	29,023
Wells Fargo Bank, N.A.
Mortgage loans sold under agreement to repurchase
Amount at risk	$ 11,917