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
Jun. 30, 2026
Dec. 31, 2025
Loans, fair value [Abstract]    
Fair value, Total $ 12,458,249 $ 8,532,644
Loans, difference, [Abstract]    
Difference 202,166 173,409
Loans held for sale [Member]    
Loans, fair value [Abstract]    
Current through 89 days delinquent 3,193,864 2,696,128
90 or more days delinquent, not in foreclosure 134 1,273
90 or more days delinquent, in foreclosure 1,345 1,997
Fair value, Total 3,195,343 2,699,398
Loans, principal amount due upon maturity [Abstract]    
Current through 89 days delinquent 3,131,455 2,627,441
90 or more days delinquent, not in foreclosure 134 1,271
90 or more days delinquent, in foreclosure 1,653 2,289
Principal amount due upon maturity 3,133,242 2,631,001
Loans, difference, [Abstract]    
Current through 89 days delinquent 62,409 68,687
90 or more days delinquent, not in foreclosure 0 2
90 or more days delinquent, in foreclosure (308) (292)
Difference 62,101 68,397
Loans held for sale [Member] | Nonperforming mortgage loans [Member]    
Loans, fair value [Abstract]    
Fair value 1,479 3,270
Loans, principal amount due upon maturity [Abstract]    
Principal amount due upon maturity 1,787 3,560
Loans, difference, [Abstract]    
Difference (308) (290)
Loans held for investment Held in consolidated VIEs [Member]    
Loans, fair value [Abstract]    
Current through 89 days delinquent 12,452,163 8,529,906
90 or more days delinquent, not in foreclosure 4,494 700
90 or more days delinquent, in foreclosure 0 333
Fair value 12,456,657 8,530,939
Loans, principal amount due upon maturity [Abstract]    
Current through 89 days delinquent 12,246,747 8,353,814
90 or more days delinquent, not in foreclosure 5,255 844
90 or more days delinquent, in foreclosure 0 428
Principal amount due upon maturity 12,252,002 8,355,086
Loans, difference, [Abstract]    
Current through 89 days delinquent 205,416 176,092
90 or more days delinquent, not in foreclosure (761) (144)
90 or more days delinquent, in foreclosure 0 (95)
Difference 204,655 175,853
Loans held for investment Held in consolidated VIEs [Member] | Nonperforming mortgage loans [Member]    
Loans, fair value [Abstract]    
Fair value 4,494 1,033
Loans, principal amount due upon maturity [Abstract]    
Principal amount due upon maturity 5,255 1,272
Loans, difference, [Abstract]    
Difference (761) (239)
Distressed at Fair Value [Member]    
Loans, fair value [Abstract]    
Current through 89 days delinquent 315 371
90 or more days delinquent, not in foreclosure 1,072 942
90 or more days delinquent, in foreclosure 205 392
Fair value 12,458,249 8,532,644
Fair value 1,592 1,705
Loans, principal amount due upon maturity [Abstract]    
Current through 89 days delinquent 407 476
90 or more days delinquent, not in foreclosure 2,949 2,553
90 or more days delinquent, in foreclosure 725 1,120
Principal amount due upon maturity 12,256,083 8,359,235
Principal amount due upon maturity 4,081 4,149
Loans, difference, [Abstract]    
Current through 89 days delinquent (92) (105)
90 or more days delinquent, not in foreclosure (1,877) (1,611)
90 or more days delinquent, in foreclosure (520) (728)
Difference (2,489) (2,444)
Distressed at Fair Value [Member] | Nonperforming mortgage loans [Member]    
Loans, fair value [Abstract]    
Fair value 1,277 1,334
Loans, principal amount due upon maturity [Abstract]    
Principal amount due upon maturity 3,674 3,673
Loans, difference, [Abstract]    
Difference $ (2,397) $ (2,339)