Loans Receivable and Allowance for Credit Losses - Additional Information (Details) $ in Thousands		3 Months Ended		12 Months Ended
		Mar. 31, 2024 USD ($) Loan	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2023 USD ($) Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of troubled debt restructured loans | Loan		20			21
Troubled debt restructured loans		$ 5,600			$ 5,900
Troubled debt restructured loan, accrual status		4,900			5,200
Loans before net deferred loan origination cost and allowance for losses on loan		2,005,418			1,921,572
Aggregate balance of grain		5,731
Allowance for credit losses	[1]	(4,868)
Microloans, net of allowance for loan losses		863
Microloans originated - put back to Grain		24,051
Grain Write-Downs		15,406
Cash Receipts From Grain		6,819
Grant/reserve (inception-to-March 31, 2024)		(1,826)
Investment in Grain wrote-off		(1,000)
Exposure to Grain	[2]	863
Grain write-off and write-down		(53)	$ (914)
Allowance for off-balance sheet credit losses		$ 3,777		$ 354	3,613
Accounting Standards Update 2022-02
Accounts, Notes, Loans and Financing Receivable [Line Items]
Change in accounting principle, accounting standards update, adopted [true false]		true
Change in accounting principle, accounting standards update, adoption date		Jan. 01, 2023
Construction Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before net deferred loan origination cost and allowance for losses on loan		$ 608,665			503,925
Provision for Contingencies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for off-balance-sheet credit loss		200	1,000
Other Liabilities
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for off-balance sheet credit losses		3,800			$ 3,600
Grain Technologies LLC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Micro loan credit limit		$ 1,500
Number of micro loan outstanding | Loan		11,939
Aggregate balance of grain		$ 5,700
Allowance for credit losses		4,900
Microloans, net of allowance for loan losses		900
Microloans originated - put back to Grain		24,100
Grain Write-Downs		(15,400)
Cash Receipts From Grain		6,800
Grant/reserve (inception-to-March 31, 2024)		1,800
Security deposits by borrowers		1,600
Investment in Grain wrote-off				$ 1,000
Exposure to Grain		900
Grain recoveries			$ 900
Grain write-off and write-down		$ 100
Grain Technologies LLC | Microloans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of micro loan outstanding | Loan		45,322
Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Strong Pass Loans to new or existing borrowers collateralized percentage		90.00%

[1] Excludes $1.6 million of security deposits by Grain originated borrowers reported in deposits in the accompanying Consolidated Statements of Financial Conditions.

[2] Total remaining exposure to Grain borrowers. These loans are now serviced by the Bank.