Fair Value - Financial Assets and Liabilities Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Financial Assets and Liabilities Measured on a Recurring Basis
Securities available-for-sale	$ 237,612	$ 442,636
U.S. Treasury
Financial Assets and Liabilities Measured on a Recurring Basis
Securities available-for-sale	184,162	382,369
Agency mortgage-backed securities
Financial Assets and Liabilities Measured on a Recurring Basis
Securities available-for-sale	53,450	60,267
Significant Other Observable Inputs (Level 2) | Agency mortgage-backed securities
Financial Assets and Liabilities Measured on a Recurring Basis
Securities available-for-sale		60,267
Recurring basis
Financial Assets and Liabilities Measured on a Recurring Basis
I/O strip receivables	95	117
Transfers between Level 1 and Level 2:
Transfers between Level 1 and Level 2	0	0
Recurring basis | U.S. Treasury
Financial Assets and Liabilities Measured on a Recurring Basis
Securities available-for-sale	184,162	382,369
Recurring basis | Agency mortgage-backed securities
Financial Assets and Liabilities Measured on a Recurring Basis
Securities available-for-sale	53,450
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Treasury
Financial Assets and Liabilities Measured on a Recurring Basis
Securities available-for-sale	184,162	382,369
Recurring basis | Significant Other Observable Inputs (Level 2)
Financial Assets and Liabilities Measured on a Recurring Basis
I/O strip receivables	95	$ 117
Recurring basis | Significant Other Observable Inputs (Level 2) | Agency mortgage-backed securities
Financial Assets and Liabilities Measured on a Recurring Basis
Securities available-for-sale	$ 53,450