v3.26.1
Fair Value - Fair Values and Related Principal Amounts Due upon Maturity of Loans Accounted for Under Fair Value Option (Detail) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Loans, fair value [Abstract]    
Fair value, Total $ 10,867,942 $ 8,532,644
Loans, difference, [Abstract]    
Difference 281,181 173,409
Loans held for sale [Member]    
Loans, fair value [Abstract]    
Current through 89 days delinquent 2,347,431 2,696,128
90 or more days delinquent, not in foreclosure 1,177 1,273
90 or more days delinquent, in foreclosure 1,287 1,997
Fair value, Total 2,349,895 2,699,398
Loans, principal amount due upon maturity [Abstract]    
Current through 89 days delinquent 2,303,642 2,627,441
90 or more days delinquent, not in foreclosure 1,234 1,271
90 or more days delinquent, in foreclosure 1,699 2,289
Principal amount due upon maturity 2,306,575 2,631,001
Loans, difference, [Abstract]    
Current through 89 days delinquent 43,789 68,687
90 or more days delinquent, not in foreclosure (57) 2
90 or more days delinquent, in foreclosure (412) (292)
Difference 43,320 68,397
Loans held for sale [Member] | Nonperforming mortgage loans [Member]    
Loans, fair value [Abstract]    
Fair value 2,464 3,270
Loans, principal amount due upon maturity [Abstract]    
Principal amount due upon maturity 2,933 3,560
Loans, difference, [Abstract]    
Difference (469) (290)
Loans held for investment Held in consolidated VIEs [Member]    
Loans, fair value [Abstract]    
Current through 89 days delinquent 10,863,057 8,529,906
90 or more days delinquent, not in foreclosure 3,087 700
90 or more days delinquent, in foreclosure 148 333
Fair value 10,866,292 8,530,939
Loans, principal amount due upon maturity [Abstract]    
Current through 89 days delinquent 10,578,933 8,353,814
90 or more days delinquent, not in foreclosure 3,499 844
90 or more days delinquent, in foreclosure 195 428
Principal amount due upon maturity 10,582,627 8,355,086
Loans, difference, [Abstract]    
Current through 89 days delinquent 284,124 176,092
90 or more days delinquent, not in foreclosure (412) (144)
90 or more days delinquent, in foreclosure (47) (95)
Difference 283,665 175,853
Loans held for investment Held in consolidated VIEs [Member] | Nonperforming mortgage loans [Member]    
Loans, fair value [Abstract]    
Fair value 3,235 1,033
Loans, principal amount due upon maturity [Abstract]    
Principal amount due upon maturity 3,694 1,272
Loans, difference, [Abstract]    
Difference (459) (239)
Distressed at Fair Value [Member]    
Loans, fair value [Abstract]    
Current through 89 days delinquent 362 371
90 or more days delinquent, not in foreclosure 901 942
90 or more days delinquent, in foreclosure 387 392
Fair value 10,867,942 8,532,644
Fair value 1,650 1,705
Loans, principal amount due upon maturity [Abstract]    
Current through 89 days delinquent 457 476
90 or more days delinquent, not in foreclosure 2,413 2,553
90 or more days delinquent, in foreclosure 1,264 1,120
Principal amount due upon maturity 10,586,761 8,359,235
Principal amount due upon maturity 4,134 4,149
Loans, difference, [Abstract]    
Current through 89 days delinquent (95) (105)
90 or more days delinquent, not in foreclosure (1,512) (1,611)
90 or more days delinquent, in foreclosure (877) (728)
Difference (2,484) (2,444)
Distressed at Fair Value [Member] | Nonperforming mortgage loans [Member]    
Loans, fair value [Abstract]    
Fair value 1,288 1,334
Loans, principal amount due upon maturity [Abstract]    
Principal amount due upon maturity 3,677 3,673
Loans, difference, [Abstract]    
Difference $ (2,389) $ (2,339)