Loans and Allowance for Loan Losses - Changes in allowance (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Changes in the allowance
Beginning Balance	$ 33,764	$ 27,256	$ 34,246	$ 23,924
Provision for loan losses	(2,000)	3,500	(2,000)	9,500
Loan charge-offs	(793)	(51)	(1,899)	(3,816)
Loan recoveries	1,095	632	1,719	1,729
Ending Balance	32,066	31,337	32,066	31,337
Unallocated
Changes in the allowance
Beginning Balance	2,469	1,747	1,378	2,192
Provision for loan losses	(1,453)	648	(362)	203
Ending Balance	1,016	2,395	1,016	2,395
Commercial
Changes in the allowance
Beginning Balance	23,144	21,188	24,968	19,261
Provision for loan losses	(1,146)	1,022	(2,406)	5,635
Loan charge-offs	(747)	(10)	(1,760)	(3,610)
Loan recoveries	1,052	527	1,501	1,441
Ending Balance	22,303	22,727	22,303	22,727
Commercial \| Commercial and industrial
Changes in the allowance
Beginning Balance	9,620	10,797	10,205	12,270
Provision for loan losses	(825)	(846)	(1,378)	(498)
Loan charge-offs	(747)	(10)	(1,224)	(2,745)
Loan recoveries	1,052	432	1,497	1,346
Ending Balance	9,100	10,373	9,100	10,373
Commercial \| Real estate construction
Changes in the allowance
Beginning Balance	587	443	658	303
Provision for loan losses	92	40	21	180
Ending Balance	679	483	679	483
Commercial \| Commercial real estate
Changes in the allowance
Beginning Balance	12,937	9,948	14,105	6,688
Provision for loan losses	(413)	1,828	(1,049)	5,953
Loan charge-offs			(536)	(865)
Loan recoveries		95	4	95
Ending Balance	12,524	11,871	12,524	11,871
Consumer
Changes in the allowance
Beginning Balance	8,151	4,321	7,900	2,471
Provision for loan losses	599	1,830	768	3,662
Loan charge-offs	(46)	(41)	(139)	(206)
Loan recoveries	43	105	218	288
Ending Balance	8,747	6,215	8,747	6,215
Consumer \| Residential \| Real estate first mortgage
Changes in the allowance
Beginning Balance	6,176	2,673	5,774	1,448
Provision for loan losses	625	1,694	1,027	2,914
Loan recoveries				5
Ending Balance	6,801	4,367	6,801	4,367
Consumer \| Residential \| Real estate junior lien
Changes in the allowance
Beginning Balance	1,401	1,102	1,373	671
Provision for loan losses	6	28	(63)	377
Loan charge-offs				(12)
Loan recoveries	16	81	113	175
Ending Balance	1,423	1,211	1,423	1,211
Consumer \| Other revolving and installment
Changes in the allowance
Beginning Balance	574	546	753	352
Provision for loan losses	(32)	108	(196)	371
Loan charge-offs	(46)	(41)	(139)	(194)
Loan recoveries	27	24	105	108
Ending Balance	$ 523	$ 637	$ 523	$ 637

Amount of increase in allowance for credit loss on accounts receivable, from recovery.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (e)
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- Definition

Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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- Definition

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

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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- Definition

Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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