Quarterly report pursuant to Section 13 or 15(d)

Mortgage Servicing Rights, at Fair Value - Summary of Servicing Portfolio and its Activities (Detail)

v3.21.2
Mortgage Servicing Rights, at Fair Value - Summary of Servicing Portfolio and its Activities (Detail) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2021
Mar. 31, 2021
Sep. 30, 2020
Sep. 30, 2021
Sep. 30, 2021
Sep. 30, 2020
Dec. 31, 2020
Servicing Assets at Fair Value [Line Items]              
Servicing rights $ 34,091,115     $ 34,091,115 $ 34,091,115   $ 22,269,362
Weighted average interest rate         3.00%   3.10%
Changes in fair value due to:              
Ending Balance 34,091,115     34,091,115 $ 34,091,115    
Capitalized servicing rights [Member]              
Servicing Assets at Fair Value [Line Items]              
Beginning balance 30,592,187 $ 22,269,362 $ 7,211,843 26,675,358 22,269,362 $ 288,057 $ 288,057
Originations 5,380,307 6,312,227 7,308,891 10,520,166   14,295,128  
Purchases 228,470 866,806   234,007      
Payoffs, sales and curtailments (2,109,849) (2,773,037) (243,225) (3,338,416)   (305,676)  
Changes in fair value due to:              
Ending Balance 34,091,115 26,675,358 14,277,509 34,091,115 34,091,115 14,277,509 22,269,362
Mortgage Servicing Rights [Member]              
Servicing Assets at Fair Value [Line Items]              
Beginning balance 290,938 180,684 42,684 267,364 180,684 2,600 2,600
Originations 52,252 65,964 53,401 102,301   98,256  
Purchases 2,291 9,014   2,352      
Payoffs, sales and curtailments (2,501) (8,647)   (2,501)      
Changes in fair value due to:              
Changes in market inputs or assumptions used in valuation model 13,165 35,109 8,170 (2,886)   4,746  
Changes in fair value due to portfolio runoff and other (15,196) (14,760) (3,716) (25,681)   (5,063)  
Ending Balance 340,949 $ 267,364 $ 100,539 340,949 340,949 $ 100,539 180,684
Federal National Mortgage Association Certificates and Obligations (FNMA) [Member]              
Servicing Assets at Fair Value [Line Items]              
Servicing rights 33,034,877     33,034,877 33,034,877   20,501,504
Government National Mortgage Association Certificates and Obligations (GNMA) [Member]              
Servicing Assets at Fair Value [Line Items]              
Servicing rights 235,279     235,279 235,279   1,727,831
Private Investors [Member]              
Servicing Assets at Fair Value [Line Items]              
Servicing rights $ 820,959     $ 820,959 $ 820,959   $ 40,027