Investments - Investments by contractual maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Schedule of Available-for-sale Securities
Within one year, amortized cost	$ 0	$ 0
Within one year, estimated fair value	0	0
After one year through five years, amortized cost	15,661	9,992
After one year through five years, estimated fair value	14,400	8,954
After five years through ten years, amortized cost	33,693	40,264
After five years through ten years, estimated fair value	30,833	35,379
After ten years, amortized cost	145,134	157,804
After ten years, estimated fair value	133,144	144,843
Total allocated, amortized cost	194,488	208,060
Total allocated, estimated fair value	178,377	189,176
Amortized  Cost	553,963	669,646
Debt Securities, Available-for-sale	503,964	597,196
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value	0	0
Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, Year One	0	0
Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five	24,081	8,136
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year One through Five	24,538	8,463
Debt Securities, Held-to-maturity, Maturity, Rolling after Five Through Ten Years, Weighted Average Yield	59,110	74,746
Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10	56,146	68,552
Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10	101,269	101,264
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year 10	108,495	108,861
Held-to-maturity investment securities	192,143	192,070
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Total	181,496	177,952
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, without Single Maturity Date	302,777	303,493
Debt Securities, Held-to-maturity, Maturity, without Single Maturity Date, Fair Value	283,353	277,003
U.S. Government agencies
Schedule of Available-for-sale Securities
Investment securities not due at a single maturity date, amortized cost	71	102
Investment securities not due at a single maturity date, estimated fair value	68	95
Amortized  Cost	71	102
Debt Securities, Available-for-sale	68	95
U.S. Government sponsored entities and agencies collateralized by residential mortgage obligations
Schedule of Available-for-sale Securities
Investment securities not due at a single maturity date, amortized cost	79,261	88,874
Investment securities not due at a single maturity date, estimated fair value	75,686	83,352
Amortized  Cost	79,261	88,874
Debt Securities, Available-for-sale	75,686	83,352
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, without Single Maturity Date	11,010	10,758
Debt Securities, Held-to-maturity, Maturity, without Single Maturity Date, Fair Value	9,458	9,066
Private label mortgage and asset backed securities
Schedule of Available-for-sale Securities
Investment securities not due at a single maturity date, amortized cost	279,688	372,610
Investment securities not due at a single maturity date, estimated fair value	249,352	324,573
Amortized  Cost	279,688	372,610
Debt Securities, Available-for-sale	249,352	324,573
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, without Single Maturity Date	53,457	54,579
Debt Securities, Held-to-maturity, Maturity, without Single Maturity Date, Fair Value	49,345	48,635
Corporate debt securities
Schedule of Available-for-sale Securities
Investment securities not due at a single maturity date, amortized cost	455	0
Investment securities not due at a single maturity date, estimated fair value	481	0
Amortized  Cost	455
Debt Securities, Available-for-sale	481
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, without Single Maturity Date	46,167	46,086
Debt Securities, Held-to-maturity, Maturity, without Single Maturity Date, Fair Value	$ 43,054	$ 41,350