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Loans and Allowance for Credit Losses on Loans - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 19,958		$ 22,874
Provision (reversal) - CECL	(920)		(3,849)
Charge-offs	0		0
Recoveries	62		75
Ending balance	19,100		19,100
Beginning balance		$ 18,884		$ 16,677
Provision - incurred loss		2,000	(3,849)	4,200
Charge-offs		(20)		(20)
Recoveries		4		11
Ending balance		20,868		20,868
Commercial loans | Commercial and industrial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,654		2,530
Provision (reversal) - CECL	(68)		(947)
Charge-offs	0		0
Recoveries	4		7
Ending balance	1,590		1,590
Beginning balance		2,784		2,334
Provision - incurred loss		(159)		287
Charge-offs		(20)		(20)
Recoveries		4		8
Ending balance		2,609		2,609
Commercial real estate loans | Commercial owner-occupied
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,304		2,778
Provision (reversal) - CECL	(267)		(741)
Charge-offs	0		0
Recoveries	0		0
Ending balance	2,037		2,037
Beginning balance		2,797		2,462
Provision - incurred loss		113		448
Charge-offs		0		0
Recoveries		0		0
Ending balance		2,910		2,910
Commercial real estate loans | Commercial investor-owned
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	10,856		12,682
Provision (reversal) - CECL	(95)		(1,921)
Charge-offs	0		0
Recoveries	0		0
Ending balance	10,761		10,761
Beginning balance		9,225		8,483
Provision - incurred loss		1,178		1,920
Charge-offs		0		0
Recoveries		0		0
Ending balance		10,403		10,403
Commercial real estate loans | Construction
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,312		1,557
Provision (reversal) - CECL	(178)		(433)
Charge-offs	0		0
Recoveries	8		18
Ending balance	1,142		1,142
Beginning balance		727		638
Provision - incurred loss		109		195
Charge-offs		0		0
Recoveries		0		3
Ending balance		836		836
Residential loans | Home equity
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	520		738
Provision (reversal) - CECL	(158)		(376)
Charge-offs	0		0
Recoveries	50		50
Ending balance	412		412
Beginning balance		982		850
Provision - incurred loss		62		194
Charge-offs		0		0
Recoveries		0		0
Ending balance		1,044		1,044
Residential loans | Other residential
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	757		998
Provision (reversal) - CECL	(144)		(385)
Charge-offs	0		0
Recoveries	0		0
Ending balance	613		613
Beginning balance		1,098		973
Provision - incurred loss		168		293
Charge-offs		0		0
Recoveries		0		0
Ending balance		1,266		1,266
Consumer loans | Installment and other consumer loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	255		291
Provision (reversal) - CECL	(17)		(53)
Charge-offs	0		0
Recoveries	0		0
Ending balance	238		238
Beginning balance		363		284
Provision - incurred loss		63		142
Charge-offs		0		0
Recoveries		0		0
Ending balance		426		426
Unallocated
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,300		1,300
Provision (reversal) - CECL	7		1,007
Charge-offs	0		0
Recoveries	0		0
Ending balance	$ 2,307		$ 2,307
Beginning balance		908		653
Provision - incurred loss		466		721
Charge-offs		0		0
Recoveries		0		0
Ending balance		$ 1,374		$ 1,374

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- Definition

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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