Loans and Allowance for Credit Losses - Loans - ACL Loans by Portfolio Segment (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
May 19, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance		$ 32,588	$ 16,876	$ 18,957	$ 14,597
Purchase credit deteriorated loans		0		336
Charge-offs		(33)	(15)	(357)	(81)
Recoveries		22	69	63	189
Net loans (charged off) recovered		(11)		(294)
Provisions		1,427	1,550	3,074	3,775
Allowance for loan losses, ending balance		34,004	18,480	34,004	18,480
Brunswick Bancorp Acquisition
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Purchase credit deteriorated loans	$ 355
Provisions		2,000		2,000
Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance				11,931
Commercial portfolio \| Commercial real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance		14,197	11,991	13,142	9,415
Purchase credit deteriorated loans		0		314
Charge-offs		0	0	(16)	0
Recoveries		0	63	0	128
Net loans (charged off) recovered		0		(16)
Provisions		4,483	468	4,952	2,979
Allowance for loan losses, ending balance		18,680	12,522	18,680	12,522
Commercial portfolio \| Commercial real estate \| Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance				288
Commercial portfolio \| Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance		11,403	3,671	4,593	3,439
Purchase credit deteriorated loans		0		5
Charge-offs		0	(1)	(220)	(1)
Recoveries		0	0	0	13
Net loans (charged off) recovered		0		(220)
Provisions		(4,072)	879	(3,647)	1,098
Allowance for loan losses, ending balance		7,331	4,549	7,331	4,549
Commercial portfolio \| Commercial and industrial \| Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance				6,600
Commercial portfolio \| Construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance		3,667	46	0	38
Purchase credit deteriorated loans		0		13
Charge-offs		0	0	0	0
Recoveries		0	0	0	24
Net loans (charged off) recovered		0		0
Provisions		2,211	5	2,664	(11)
Allowance for loan losses, ending balance		5,878	51	5,878	51
Commercial portfolio \| Construction \| Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance				3,201
Consumer portfolio \| Residential mortgage
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance		3,145	1,143	1,319	1,019
Purchase credit deteriorated loans		0		4
Charge-offs		0	(3)	(4)	(3)
Recoveries		7	0	37	4
Net loans (charged off) recovered		7		33
Provisions		(1,060)	162	(826)	282
Allowance for loan losses, ending balance		2,092	1,302	2,092	1,302
Consumer portfolio \| Residential mortgage \| Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance				1,562
Consumer portfolio \| Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance		176	2	29	2
Purchase credit deteriorated loans		0		0
Charge-offs		(33)	(11)	(117)	(77)
Recoveries		15	6	26	20
Net loans (charged off) recovered		(18)		(91)
Provisions		(135)	5	(69)	57
Allowance for loan losses, ending balance		23	2	23	2
Consumer portfolio \| Consumer \| Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance				154
Unallocated
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance			23	(126)	684
Purchase credit deteriorated loans				0
Charge-offs			0	0	0
Recoveries			0	0	0
Net loans (charged off) recovered				0
Provisions			31	0	(630)
Allowance for loan losses, ending balance		$ 0	$ 54	0	$ 54
Unallocated \| Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance				$ 126

Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Net Writeoff (Recovery)

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- Definition

Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479344/326-20-45-1

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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Amount, excluding accrued interest, of increase in allowance for credit loss on financing receivable from recovery. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (e)
-Publisher FASB
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Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-6

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Amount, excluding accrued interest, of credit loss expense (reversal of expense) on financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

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Amount, excluding accrued interest, of allowance for credit loss at acquisition date of financing receivable purchased with credit deterioration. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
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-Section 50
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