Loans Receivable and Allowance for Credit Losses - Narrative (Details)	3 Months Ended
	Mar. 31, 2023 USD ($) loan segment	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($) loan	Dec. 31, 2021 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-for-sale	$ 0		$ 0
Gain on sale of loans held-for-sale	799,000	$ 110,000
Loss on sale of loans held-for-sale	8,000	0
Purchases of loans receivable	14,729,000	0
Financing receivable, excluding accrued interest, before allowance for credit loss	7,787,072,000		7,677,564,000
Carrying value of servicing liability	$ 520,800,000		$ 497,100,000
Threshold period, past due status of financial receivables	30 days
Threshold period, past due for nonperforming status of financial receivables	90 days		90 days
Non-accrual	$ 6,600,000		$ 6,700,000
Financing receivable, excluding accrued interest, 90 days or more past due, still accruing	0		0
Real estate owned	$ 0		$ 0
Mortgage loans in process of foreclosure, number of loans | loan	2		2
Mortgage loans in process of foreclosure, amount	$ 81,000		$ 81,000
Number of loan portfolio segments | segment	7
Accrued interest receivable on loans receivable	$ 30,500,000		29,400,000
Financing receivable modified in period, amount	0
Specific allowance for loan losses attributable to impaired loans	376,000		339,000
Impaired loans for which there are no related allowance for loan losses	16,210,000		16,557,000
Off-balance sheet, credit loss, liability	6,442,000	8,846,000	6,970,000	$ 524,000
Off-balance sheet, credit loss, liability, credit loss expense (reversal)	(528,000)	648,000
Real estate loans | One-to-four family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans held-for-sale	9,800,000
Purchases of loans receivable		0
Specific allowance for loan losses attributable to impaired loans	203,000		201,000
Impaired loans for which there are no related allowance for loan losses	1,914,000		1,296,000
Real estate loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans held-for-sale	15,400,000
Specific allowance for loan losses attributable to impaired loans	104,000		99,000
Impaired loans for which there are no related allowance for loan losses	13,899,000		14,836,000
Real estate loans | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans held-for-sale	580,000	905,000
Commercial business loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans held-for-sale	9,400,000	$ 1,300,000
Specific allowance for loan losses attributable to impaired loans	39,000		10,000
Impaired loans for which there are no related allowance for loan losses	130,000		143,000
Less Than 90 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual	$ 1,800,000		$ 1,200,000
Financial receivable, number of loans in nonaccrual status | loan	11		7
Stewardship Financial Corporation | Financial Asset Acquired with Credit Deterioration
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, excluding accrued interest, before allowance for credit loss	$ 1,800,000		$ 2,000,000
Roselle Entities | Financial Asset Acquired with Credit Deterioration
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, excluding accrued interest, before allowance for credit loss	0		184,000
Freehold Entities | Financial Asset Acquired with Credit Deterioration
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, excluding accrued interest, before allowance for credit loss	3,600,000		3,700,000
RSI Entites | Financial Asset Acquired with Credit Deterioration
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, excluding accrued interest, before allowance for credit loss	10,800,000		11,300,000
Paycheck Protection Program | Commercial business loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, excluding accrued interest, before allowance for credit loss	1,500,000		1,600,000
Financing receivable, unamortized loan fee	$ 4,000		$ 13,000