Loans Receivable and Allowance for Credit Losses - Narrative (Details)	3 Months Ended
	Mar. 31, 2024 USD ($) loan	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($) loan	Dec. 31, 2022 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-for-sale	$ 0		$ 0
Gain on sale of loans held-for-sale	185,000	$ 799,000
Loss on sale of loans held-for-sale	0	8,000
Purchases of loans receivable	0	14,729,000
Financing receivable, excluding accrued interest, before allowance for credit loss	7,815,629,000		7,874,537,000
Carrying value of servicing liability	$ 544,000,000		$ 551,000,000
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	$ 22,900,000		$ 12,600,000
Financing receivable, excluding accrued interest, 90 days or more past due, still accruing			0
Real estate owned	0		0
Accrued interest receivable on loans receivable	33,700,000		32,900,000
Specific allowance for loan losses attributable to impaired loans	359,000		614,000
Impaired loans for which there are no related allowance for loan losses	8,102,000		19,919,000
Off-balance sheet, credit loss, liability	4,654,000	6,442,000	5,484,000	$ 6,970,000
Off-balance sheet, credit loss, liability, credit loss expense (reversal)	(830,000)	(528,000)
Less Than 90 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual	$ 16,500,000		$ 1,600,000
Financial receivable, number of loans in nonaccrual status | loan	17		10
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	$ 1,600,000		$ 1,700,000
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	2,800,000
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	10,500,000		10,600,000
Real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans held-for-sale		9,400,000
Real estate loans | One-to-four family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans held-for-sale	$ 236,000	9,800,000
Mortgage loans in process of foreclosure, number of loans | loan	5
Mortgage loans in process of foreclosure, amount	$ 1,400,000
Specific allowance for loan losses attributable to impaired loans	35,000		186,000
Impaired loans for which there are no related allowance for loan losses	1,139,000		1,170,000
Real estate loans | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans held-for-sale	1,300,000	580,000
Real estate loans | Home equity loans and advances
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans held-for-sale		$ 15,400,000
Real estate loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Specific allowance for loan losses attributable to impaired loans	226,000		237,000
Impaired loans for which there are no related allowance for loan losses	1,942,000		12,741,000
Commercial business loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans held-for-sale	2,100,000
Specific allowance for loan losses attributable to impaired loans	98,000		154,000
Impaired loans for which there are no related allowance for loan losses	4,865,000		5,814,000
Commercial business loans | Paycheck Protection Program
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, excluding accrued interest, before allowance for credit loss	$ 717,000		$ 809,000
Consumer loans | Home equity loans and advances
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans in process of foreclosure, number of loans | loan	2		1
Mortgage loans in process of foreclosure, amount	$ 155,000		$ 93,000
Specific allowance for loan losses attributable to impaired loans	0		30,000
Impaired loans for which there are no related allowance for loan losses	$ 110,000		$ 145,000
Consumer loans | Residential Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans in process of foreclosure, number of loans | loan			1,000
Mortgage loans in process of foreclosure, amount			$ 576,000