Loans Receivable and Allowance for Credit Losses - Loans Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 8,221,307	$ 8,253,818
Net deferred loan costs, fees and purchased premiums and discounts	38,371	38,192
Loans receivable	8,259,678	8,292,010
Real estate loans \| One-to-four family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,544,838	2,559,519
Real estate loans \| Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,669,232	1,677,613
Real estate loans \| Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,480,804	2,521,151
Real estate loans \| Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	520,753	469,438
Home equity loans and advances \| Home equity loans and advances
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	249,487	255,126
Home equity loans and advances \| Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,850	2,895
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	8,211,149	8,243,376
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration \| Real estate loans \| One-to-four family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,543,588	2,558,252
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration \| Real estate loans \| Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,669,232	1,677,613
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration \| Real estate loans \| Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,472,993	2,513,260
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration \| Real estate loans \| Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	520,753	469,438
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration \| Commercial business loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	752,246	766,792
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration \| Home equity loans and advances \| Home equity loans and advances
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	249,487	255,126
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration \| Home equity loans and advances \| Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,850	2,895
Financial Asset Acquired with Credit Deterioration
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	10,158	10,442
Financial Asset Acquired with Credit Deterioration \| Real estate loans \| One-to-four family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,250	1,267
Financial Asset Acquired with Credit Deterioration \| Real estate loans \| Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	0	0
Financial Asset Acquired with Credit Deterioration \| Real estate loans \| Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	7,811	7,891
Financial Asset Acquired with Credit Deterioration \| Real estate loans \| Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	0	0
Financial Asset Acquired with Credit Deterioration \| Home equity loans and advances \| Home equity loans and advances
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	0	0
Financial Asset Acquired with Credit Deterioration \| Home equity loans and advances \| Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 0	$ 0

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

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Amortized cost excluding accrued interest, before allowance for credit loss, fee, and loan in process, of financing receivable. Excludes net investment in lease.

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Amount of unamortized loan commitment, origination, and other costs (fees) and purchase premium (discount) on financing receivable recognized as adjustment to yield. Excludes financing receivable covered under loss sharing agreement.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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