Loans Receivable and Allowance for Credit Losses - Narrative (Details)		12 Months Ended
	May 01, 2022 USD ($)	Dec. 31, 2022 USD ($) segment loan	Dec. 31, 2021 USD ($) loan	Dec. 31, 2020 USD ($) loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-for-sale		$ 0
Proceeds from sales of loans held-for-sale		9,639,000	$ 302,039,000	$ 111,764,000
Gain on sale of loans held-for-sale		242,000	8,600,000	1,700,000
Loss on sale of loans held-for-sale		64,000	24,000	0
Proceeds from sale of loans held-for-investment		0	0
Gain on sale of loans held-for-investment				161,000
Loss on sale of loans held-for-investment				0
Purchases and grants of loans receivable		8,315,000	85,382,000	0
Loans receivable		7,677,564,000	6,360,601,000
Carrying value of servicing liability		497,100,000	519,500,000
Servicing income		1,300,000	1,500,000	1,400,000
Proceeds from sales of loans receivable		$ 0	$ 0	35,613,000
Threshold period, past due status of financing receivables		30 days
Threshold period, past due for nonperforming status of financing receivables		90 days	90 days
Non-accrual loans		$ 6,700,000	$ 3,900,000
Increase in interest income if non-accrual had performed in line with their original terms		392,000	190,000	426,000
Cash basis interest income on non-accrual loans		161,000	242,000	$ 410,000
Loans past due		0	0
Property acquired through foreclosure		$ 0	$ 0
Number of loans in the process of foreclosure | loan		2	1
Loans in process of foreclosure		$ 81,000	$ 87,000
Number of loan portfolio segments | segment		7
Financing Receivable, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]		Accrued interest receivable
Accrued interest receivable on loans receivable		$ 29,400,000
Specific allowance for loan losses attributable to impaired loans		339,000	378,000
Impaired loans for which there are no related allowance for loan losses		16,557,000	17,280,000
Investment in troubled debt restructuring		$ 19,900,000	$ 21,300,000
Number of loans | loan		1	3	7
Stewardship Financial Corporation | Financial Asset Acquired with Credit Deterioration
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable		$ 2,000,000	$ 2,700,000
Roselle Entities | Financial Asset Acquired with Credit Deterioration
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable		184,000	184,000
Freehold Entities | Financial Asset Acquired with Credit Deterioration
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable		3,700,000	3,900,000
RSI Entities
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, purchased with credit deterioration, allowance for credit loss at acquisition date	$ 633,000
RSI Entities | Financial Asset Acquired with Credit Deterioration
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable		11,300,000
Less Than 90 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans		$ 1,200,000	$ 1,700,000
Number of loans in non-accrual status | loan		7	10
90 Days or More
Accounts, Notes, Loans and Financing Receivable [Line Items]
Investment in troubled debt restructuring		$ 23,000
Number of loans | loan		1	0
30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Investment in troubled debt restructuring			$ 36,000
Number of loans | loan			1
Related Parties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchases and grants of loans receivable		$ 751,000	$ 522,700	$ 300,000
Loans receivable		$ 9,300,000	$ 8,900,000
Number of loans granted to related party | loan		2	1	1
Freddie Mac
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans receivable		$ 0	$ 99,600,000	$ 117,300,000
Gain on sale of loans receivable			2,300,000	3,500,000
Loss on sale of loans receivable			0	0
Real estate loans | One-to-four family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans held-for-sale		2,700,000	18,500,000	111,800,000
Proceeds from sale of loans held-for-investment				15,100,000
Purchases and grants of loans receivable		8,300,000	11,800,000
Specific allowance for loan losses attributable to impaired loans		201,000	258,000
Impaired loans for which there are no related allowance for loan losses		$ 1,296,000	$ 1,882,000
Number of loans | loan		0	2
Real estate loans | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans held-for-sale		$ 4,100,000	$ 6,400,000
Proceeds from sale of loans held-for-investment				$ 13,000,000
Real estate loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans held-for-sale			19,100,000
Purchases and grants of loans receivable			73,600,000
Specific allowance for loan losses attributable to impaired loans		99,000	97,000
Impaired loans for which there are no related allowance for loan losses		$ 14,836,000	$ 13,861,000
Number of loans | loan		0	1	5
Commercial business loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans held-for-sale		$ 2,800,000	$ 258,100,000
Proceeds from sale of loans held-for-investment				$ 7,600,000
Specific allowance for loan losses attributable to impaired loans		10,000	16,000
Impaired loans for which there are no related allowance for loan losses		143,000	573,000
Number of loans | loan				2
Commercial business loans | Paycheck Protection Program
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable		1,600,000	44,900,000
Financing receivable, unamortized loan cost (fee)		$ (13,000)	$ (1,200,000)