Loans and Allowance for Loan Losses - Changes in allowance (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Changes in the allowance
Beginning Balance	$ 33,758	$ 27,019	$ 34,246	$ 23,924
Provision for loan losses		3,500		6,000
Loan charge-offs	(322)	(3,666)	(1,106)	(3,765)
Loan recoveries	328	403	624	1,097
Ending Balance	33,764	27,256	33,764	27,256
Unallocated
Changes in the allowance
Beginning Balance	823	1,833	1,378	2,192
Provision for loan losses	1,646	(86)	1,091	(445)
Ending Balance	2,469	1,747	2,469	1,747
Commercial
Changes in the allowance
Beginning Balance	24,934	21,511	24,968	19,261
Provision for loan losses	(1,793)	2,924	(1,260)	4,613
Loan charge-offs	(273)	(3,568)	(1,013)	(3,600)
Loan recoveries	276	321	449	914
Ending Balance	23,144	21,188	23,144	21,188
Commercial \| Commercial and industrial
Changes in the allowance
Beginning Balance	10,487	12,901	10,205	12,270
Provision for loan losses	(869)	278	(553)	348
Loan charge-offs	(273)	(2,703)	(477)	(2,735)
Loan recoveries	275	321	445	914
Ending Balance	9,620	10,797	9,620	10,797
Commercial \| Real estate construction
Changes in the allowance
Beginning Balance	598	334	658	303
Provision for loan losses	(11)	109	(71)	140
Ending Balance	587	443	587	443
Commercial \| Commercial real estate
Changes in the allowance
Beginning Balance	13,849	8,276	14,105	6,688
Provision for loan losses	(913)	2,537	(636)	4,125
Loan charge-offs		(865)	(536)	(865)
Loan recoveries	1		4
Ending Balance	12,937	9,948	12,937	9,948
Consumer
Changes in the allowance
Beginning Balance	8,001	3,675	7,900	2,471
Provision for loan losses	147	662	169	1,832
Loan charge-offs	(49)	(98)	(93)	(165)
Loan recoveries	52	82	175	183
Ending Balance	8,151	4,321	8,151	4,321
Consumer \| Residential \| Real estate first mortgage
Changes in the allowance
Beginning Balance	6,047	2,209	5,774	1,448
Provision for loan losses	129	459	402	1,220
Loan recoveries		5		5
Ending Balance	6,176	2,673	6,176	2,673
Consumer \| Residential \| Real estate junior lien
Changes in the allowance
Beginning Balance	1,288	1,025	1,373	671
Provision for loan losses	99	32	(69)	349
Loan charge-offs		(12)		(12)
Loan recoveries	14	57	97	94
Ending Balance	1,401	1,102	1,401	1,102
Consumer \| Other revolving and installment
Changes in the allowance
Beginning Balance	666	441	753	352
Provision for loan losses	(81)	171	(164)	263
Loan charge-offs	(49)	(86)	(93)	(153)
Loan recoveries	38	20	78	84
Ending Balance	$ 574	$ 546	$ 574	$ 546

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)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447

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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.

+ References

No definition available.

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- Definition

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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-Topic 310
-SubTopic 10
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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.

+ References

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