Borrowings - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Line Of Credit Facility [Line Items]
Advance from the Federal Home Loan Bank	$ 261,400,000		$ 261,400,000		$ 106,300,000
Guarantee from the FHLBNY through a standby letter of credit	21,500,000		21,500,000		21,500,000
Unsecured fed fund line amount outstanding	25,000,000.0		25,000,000.0		25,000,000.0
Unsecured fed fund line amount outstanding					14,910,000
Repayments of advances from FHLBNY			2,955,755,000	$ 22,500,000
Interest expense on FHLBNY advances	1,500,000	$ 549,000	2,500,000	1,600,000
Interest Expense on overnight advances	290,000	0	290,000	0
Collateral in residential 1-4 and multifamily mortgage loans available to secure advances from the FHLBNY	1,415,373,000		$ 1,415,373,000		$ 1,322,098,000
Line of credit facility, effective interest rate					3.35%
Warehouse line of credit termination date			Mar. 31, 2022
Interest expense	4,023,000	1,985,000	$ 7,382,000	6,382,000
Mortgage loans funding payable	0		0		$ 0
Asset Pledged as Collateral without Right
Line Of Credit Facility [Line Items]
Collateral in residential 1-4 and multifamily mortgage loans available to secure advances from the FHLBNY	426,000,000.0		426,000,000.0		362,300,000
Overnight Line of Credit Advance
Line Of Credit Facility [Line Items]
Advance from the Federal Home Loan Bank	25,000,000.0		$ 25,000,000.0		0
Warehouse Line of Credit #1
Line Of Credit Facility [Line Items]
Unsecured fed fund line amount outstanding					8,636,000
Debt Instrument, Interest Rate, Basis for Effective Rate			The interest rate is based on the 30-day LIBOR rate plus 3.25%.
Warehouse Line of Credit #1 | Variable Rate Above LIBOR
Line Of Credit Facility [Line Items]
Interest rate, LIBOR/Variable rate			3.25%
Warehouse Line of Credit #2
Line Of Credit Facility [Line Items]
Unsecured fed fund line amount outstanding					$ 6,274,000
Debt Instrument, Interest Rate, Basis for Effective Rate			The interest rate is based on the 30-day LIBOR rate plus 3.00%
Line of credit facility, effective interest rate					3.10%
Interest expense	0	$ 72,000	$ 70,000	$ 284,000,000
Warehouse Line of Credit #2 | Variable Rate Above LIBOR
Line Of Credit Facility [Line Items]
Interest rate, LIBOR/Variable rate			3.00%
FHLBNY
Line Of Credit Facility [Line Items]
Unsecured fed fund line amount outstanding	$ 0		$ 0		$ 0
Proceeds from advances of FHLBNY			3,140,000,000
Repayments of advances from FHLBNY			$ 2,960,000,000