Relationship with Bayview Lending Group LLC and Bayview Financial Holdings, L.P. - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule of Equity Method Investments [Line Items]
Loan facility carrying amount	$ 3,964,537	$ 3,485,369
Bayview Lending Group [Member]
Schedule of Equity Method Investments [Line Items]
Minority interest in Bayview Lending Group LLC	20.00%
Carrying value of minority interest investment in Bayview Lending Group LLC	$ 0
Bayview Lending Group [Member] | Other Revenues From Operations [Member]
Schedule of Equity Method Investments [Line Items]
Income (loss) from equity method investments	30,000	30,000	$ 53,000
Bayview Lending Group and Bayview Financial [Member]
Schedule of Equity Method Investments [Line Items]
Outstanding principal balances of mortgage servicing rights	1,400,000	1,600,000
Revenue from contract with customer	8,000	9,000	10,000
Bayview Financial [Member]
Schedule of Equity Method Investments [Line Items]
Outstanding principal balances of residential mortgage loans from Bayview Financial	96,000	74,700,000
Revenues from sub-servicing	154,000	153,000	$ 129,000
Investment securities in held-to-maturity portfolio securitized by Bayview Financial	50,000	62,000
FHA gauranteed purchase amount of deliquent loan		1,000,000
Bayview Financial [Member] | FHA Guaranteed Mortgage Loans [Member]
Schedule of Equity Method Investments [Line Items]
FHA gauranteed mortgage loan		$ 965,000
Bayview Financial [Member] | Syndicated Loan Facility [Member]
Schedule of Equity Method Investments [Line Items]
Loan facility carrying amount	2,300,000
Bayview Financial [Member] | Syndicated Loan Facility [Member] | M&T Bank [Member]
Schedule of Equity Method Investments [Line Items]
Loan facility carrying amount	$ 368,000