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Loans and Allowance for Loan Losses - Credit Risk Profile by Internally Assigned Risk Grade (Details) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Financing Receivable, Recorded Investment [Line Items] |  |
Total loans | $ 1,679,013 | $ 1,486,616
Pass |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total loans | 1,629,865 | 1,451,049
Special Mention |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total loans | 21,242 | 15,937
Substandard |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total loans | 27,906 | 19,630
Commercial | Commercial and industrial |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 235,770 | 218,575
Total loans | 235,835 | 218,615
Commercial | Pass | Commercial and industrial |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 214,636 | 201,987
Commercial | Special Mention | Commercial and industrial |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 9,318 | 9,197
Commercial | Substandard | Commercial and industrial |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 11,816 | 7,391
Commercial real estate | Commercial real estate, owner-occupied |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 299,797 | 246,641
Total loans | 300,963 | 247,713
Commercial real estate | Commercial real estate, investor |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 822,194 | 722,522
Total loans | 822,984 | 724,228
Commercial real estate | Construction |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 63,828 | 74,809
Total loans | 63,828 | 74,809
Commercial real estate | Pass | Commercial real estate, owner-occupied |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 281,104 | 234,849
Commercial real estate | Pass | Commercial real estate, investor |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 818,570 | 720,417
Commercial real estate | Pass | Construction |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 60,859 | 71,564
Commercial real estate | Special Mention | Commercial real estate, owner-occupied |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 9,284 | 4,799
Commercial real estate | Special Mention | Commercial real estate, investor |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 1,850 | 607
Commercial real estate | Special Mention | Construction |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 0 | 0
Commercial real estate | Substandard | Commercial real estate, owner-occupied |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 9,409 | 6,993
Commercial real estate | Substandard | Commercial real estate, investor |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 1,774 | 1,498
Commercial real estate | Substandard | Construction |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 2,969 | 3,245
Residential loans | Home equity |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 132,373 | 117,105
Total loans | 132,467 | 117,207
Residential loans | Other residential |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total loans | 95,526 | 78,549
Residential loans | Pass | Home equity |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 130,558 | 115,680
Residential loans | Pass | Other residential |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total loans | 95,526 | 78,549
Residential loans | Special Mention | Home equity |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 0 | 1,334
Residential loans | Special Mention | Other residential |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total loans | 0 | 0
Residential loans | Substandard | Home equity |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Loans excluding purchased credit-impaired loans | 1,815 | 91
Residential loans | Substandard | Other residential |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total loans | 0 | 0
Consumer loans | Installment and other consumer |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total loans | 27,410 | 25,495
Consumer loans | Pass | Installment and other consumer |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total loans | 27,287 | 25,083
Consumer loans | Special Mention | Installment and other consumer |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total loans | 0 | 0
Consumer loans | Substandard | Installment and other consumer |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Total loans | 123 | 412
Receivables Acquired with Deteriorated Credit Quality |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Purchased credit-impaired | 2,115 | 2,920
Receivables Acquired with Deteriorated Credit Quality | Pass |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Purchased credit-impaired | 1,325 | 2,920
Receivables Acquired with Deteriorated Credit Quality | Special Mention |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Purchased credit-impaired | 790 | 0
Receivables Acquired with Deteriorated Credit Quality | Substandard |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Purchased credit-impaired | 0 | 0
Receivables Acquired with Deteriorated Credit Quality | Commercial | Commercial and industrial |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Purchased credit-impaired | 65 | 40
Receivables Acquired with Deteriorated Credit Quality | Commercial real estate | Commercial real estate, owner-occupied |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Purchased credit-impaired | 1,166 | 1,072
Receivables Acquired with Deteriorated Credit Quality | Commercial real estate | Commercial real estate, investor |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Purchased credit-impaired | 790 | 1,706
Receivables Acquired with Deteriorated Credit Quality | Commercial real estate | Construction |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Purchased credit-impaired | 0 | 0
Receivables Acquired with Deteriorated Credit Quality | Residential loans | Home equity |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Purchased credit-impaired | 94 | 102
Receivables Acquired with Deteriorated Credit Quality | Residential loans | Other residential |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Purchased credit-impaired | 0 | 0
Receivables Acquired with Deteriorated Credit Quality | Consumer loans | Installment and other consumer |  |
Financing Receivable, Recorded Investment [Line Items] |  |
Purchased credit-impaired | $ 0 | $ 0

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- Definition Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524 + Details
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