Short-Term Debt - Mortgage Loans Sold Under Agreement to Repurchase by Counterparty (Details) - Loan Repo Facility $ in Thousands	Mar. 31, 2025 USD ($)
Atlas Securitized Products, L.P., Goldman Sachs Bank USA, Nomura Corporate Funding Americas and Mizuho Bank, Ltd
Mortgage loans sold under agreement to repurchase
Amount at risk	$ 5,919,844
Royal Bank of Canada
Mortgage loans sold under agreement to repurchase
Amount at risk	47,349
Bank of America, N.A.
Mortgage loans sold under agreement to repurchase
Amount at risk	88,190
Atlas Securitized Products, L.P.
Mortgage loans sold under agreement to repurchase
Amount at risk	156,111
BNP Paribas
Mortgage loans sold under agreement to repurchase
Amount at risk	24,716
Barclays Capital
Mortgage loans sold under agreement to repurchase
Amount at risk	24,258
Citibank, N.A.
Mortgage loans sold under agreement to repurchase
Amount at risk	39,446
Wells Fargo Bank, N.A.
Mortgage loans sold under agreement to repurchase
Amount at risk	16,838
Morgan Stanley Bank, N.A.
Mortgage loans sold under agreement to repurchase
Amount at risk	21,106
Goldman Sachs
Mortgage loans sold under agreement to repurchase
Amount at risk	8,653
JPMorgan Chase Bank, N.A.
Mortgage loans sold under agreement to repurchase
Amount at risk	$ 52,021