Acquisitions - Assets Acquired and Liabilities Assumed in Acquisition (Details) - RSI Entites - USD ($) $ in Thousands	May 01, 2022	Sep. 30, 2023	Dec. 31, 2022
Assets acquired:
Cash and cash equivalents	$ 140,769
Debt securities available for sale	79,024
Equity securities	1,075
Federal Home Loan Bank Stock	906
Loans receivable	335,501
Accrued interest receivable	910
Office properties and equipment, net	7,296
Bank-owned life insurance	13,033
Deferred tax asset, net	3,633
Core deposit intangibles	10,271
Other assets	2,723
Total assets acquired	595,141
Liabilities assumed:
Deposits	502,732
Borrowings	5,762
Advance payments by borrowers for taxes and insurance	1,341
Accrued expenses and other liabilities	10,568
Total liabilities assumed	520,403
Net assets acquired	74,738
Fair market value of stock issued to Columbia Bank MHC for purchase	102,741
Goodwill recorded at merger	$ 28,003	$ 25,500	$ 25,500