Borrowings (Schedule of Debt Repayments) (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Debt Instrument [Line Items]
Expected principal repayments related to consolidated residential mortgage loan securitizations	$ 896,600
Expected Principal Repayments Related to Consolidated Reverse Mortgage Loan Securitizations	121,800
Repurchase Agreements
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Rolling Twelve Months	2,480,288
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Two	37,459
Long-Term Debt, Maturities, Repayments of Principal in Rolling Year Three	0
Long-Term Debt, Maturities, Repayments of Principal in Rolling Year Four	0
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	0
Total Scheduled Repayment of Principal	2,517,747
Other Secured Borrowings
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Rolling Twelve Months	377,346
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Two	255,077
Long-Term Debt, Maturities, Repayments of Principal in Rolling Year Three	232,158
Long-Term Debt, Maturities, Repayments of Principal in Rolling Year Four	184,251
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	150,451
Total Scheduled Repayment of Principal	1,199,283
HMBS-related obligations
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Rolling Twelve Months	1,231,518
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Two	949,487
Long-Term Debt, Maturities, Repayments of Principal in Rolling Year Three	910,446
Long-Term Debt, Maturities, Repayments of Principal in Rolling Year Four	838,304
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	851,779
Total Scheduled Repayment of Principal	4,781,534
Unsecured Borrowings
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Rolling Twelve Months	34,931
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Two	0
Long-Term Debt, Maturities, Repayments of Principal in Rolling Year Three	37,750
Long-Term Debt, Maturities, Repayments of Principal in Rolling Year Four	210,000
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	0
Total Scheduled Repayment of Principal	282,681
Total
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Rolling Twelve Months	4,124,083
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Two	1,242,023
Long-Term Debt, Maturities, Repayments of Principal in Rolling Year Three	1,180,354
Long-Term Debt, Maturities, Repayments of Principal in Rolling Year Four	1,232,555
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	1,002,230
Total Scheduled Repayment of Principal	$ 8,781,245