Fair Value Measurements - Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	$ 743,699	$ 952,173
Trading securities	11,504	10,751
Individually evaluated loans	4,374	4,640
Investment measured at fair value	10,300	10,100
U.S. Government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	72,309	72,076
Pass-through certificates, GSE
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	347,044	432,618
Other debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	102,786	182,755
Measured on a recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	743,699	952,173
Trading securities	11,504	10,751
Equity securities	348	361
Total	755,551	963,285
Measured on a recurring basis | U.S. Government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	72,309	72,076
Measured on a recurring basis | Mortgage-backed securities:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	568,604	697,342
Measured on a recurring basis | Pass-through certificates, GSE
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	347,044	432,618
Measured on a recurring basis | REMICs, GSE
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	221,560	264,724
Measured on a recurring basis | Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	763	21
Measured on a recurring basis | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	102,023	182,734
Measured on a recurring basis | Other debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	102,786	182,755
Measured on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	0	0
Trading securities	11,504	10,751
Equity securities	348	361
Total	11,852	11,112
Measured on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	0	0
Measured on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Mortgage-backed securities:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	0	0
Measured on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pass-through certificates, GSE
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	0	0
Measured on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | REMICs, GSE
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	0	0
Measured on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	0	0
Measured on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	0	0
Measured on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	0	0
Measured on a recurring basis | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	743,699	952,173
Trading securities	0	0
Equity securities	0	0
Total	743,699	952,173
Measured on a recurring basis | Significant Other Observable Inputs (Level 2) | U.S. Government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	72,309	72,076
Measured on a recurring basis | Significant Other Observable Inputs (Level 2) | Mortgage-backed securities:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	568,604	697,342
Measured on a recurring basis | Significant Other Observable Inputs (Level 2) | Pass-through certificates, GSE
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	347,044	432,618
Measured on a recurring basis | Significant Other Observable Inputs (Level 2) | REMICs, GSE
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	221,560	264,724
Measured on a recurring basis | Significant Other Observable Inputs (Level 2) | Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	763	21
Measured on a recurring basis | Significant Other Observable Inputs (Level 2) | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	102,023	182,734
Measured on a recurring basis | Significant Other Observable Inputs (Level 2) | Other debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	102,786	182,755
Measured on a recurring basis | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	0	0
Trading securities	0	0
Equity securities	0	0
Total	0	0
Measured on a recurring basis | Significant Unobservable Inputs (Level 3) | U.S. Government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	0	0
Measured on a recurring basis | Significant Unobservable Inputs (Level 3) | Mortgage-backed securities:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	0	0
Measured on a recurring basis | Significant Unobservable Inputs (Level 3) | Pass-through certificates, GSE
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	0	0
Measured on a recurring basis | Significant Unobservable Inputs (Level 3) | REMICs, GSE
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	0	0
Measured on a recurring basis | Significant Unobservable Inputs (Level 3) | Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	0	0
Measured on a recurring basis | Significant Unobservable Inputs (Level 3) | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	0	0
Measured on a recurring basis | Significant Unobservable Inputs (Level 3) | Other debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale	0	0
Measured on a non-recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	4,374	4,640
Measured on a non-recurring basis | Real estate loans:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	4,314	4,578
Measured on a non-recurring basis | Real estate loans: | Commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	2,376	2,631
Measured on a non-recurring basis | Real estate loans: | Multifamily
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	1,917	1,923
Measured on a non-recurring basis | Real estate loans: | Home equity and lines of credit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	21	24
Measured on a non-recurring basis | Commercial and industrial loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	60	62
Measured on a non-recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	0	0
Measured on a non-recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Real estate loans:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	0	0
Measured on a non-recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Real estate loans: | Commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	0	0
Measured on a non-recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Real estate loans: | Multifamily
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	0	0
Measured on a non-recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Real estate loans: | Home equity and lines of credit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	0	0
Measured on a non-recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial and industrial loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	0	0
Measured on a non-recurring basis | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	0	0
Measured on a non-recurring basis | Significant Other Observable Inputs (Level 2) | Real estate loans:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	0	0
Measured on a non-recurring basis | Significant Other Observable Inputs (Level 2) | Real estate loans: | Commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	0	0
Measured on a non-recurring basis | Significant Other Observable Inputs (Level 2) | Real estate loans: | Multifamily
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	0	0
Measured on a non-recurring basis | Significant Other Observable Inputs (Level 2) | Real estate loans: | Home equity and lines of credit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	0	0
Measured on a non-recurring basis | Significant Other Observable Inputs (Level 2) | Commercial and industrial loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	0	0
Measured on a non-recurring basis | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	4,374	4,640
Measured on a non-recurring basis | Significant Unobservable Inputs (Level 3) | Real estate loans:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	4,314	4,578
Measured on a non-recurring basis | Significant Unobservable Inputs (Level 3) | Real estate loans: | Commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	2,376	2,631
Measured on a non-recurring basis | Significant Unobservable Inputs (Level 3) | Real estate loans: | Multifamily
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	1,917	1,923
Measured on a non-recurring basis | Significant Unobservable Inputs (Level 3) | Real estate loans: | Home equity and lines of credit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	21	24
Measured on a non-recurring basis | Significant Unobservable Inputs (Level 3) | Commercial and industrial loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually evaluated loans	$ 60	$ 62