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Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Risk Rating Categories of Loans and Leases Considered for Inclusion in Allowance for Loan and Lease Losses Calculation (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	$ 2,277,492	$ 2,148,011	$ 1,345,437
Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	891,693	796,344	533,695
Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	577,218	610,738	484,335
Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	105,429	140,766	40,232
Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	521,238	438,238	165,696
Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	4,228	2,959	1,926
Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	177,686	158,966	$ 119,553
Loans Excluding Acquired Impaired Loans
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,949,802	1,743,974
Loans Excluding Acquired Impaired Loans | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	724,981	589,041
Loans Excluding Acquired Impaired Loans | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	432,656	435,021
Loans Excluding Acquired Impaired Loans | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	99,483	133,787
Loans Excluding Acquired Impaired Loans | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	511,230	424,774
Loans Excluding Acquired Impaired Loans | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	3,766	2,385
Loans Excluding Acquired Impaired Loans | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	177,686	158,966
Loans Excluding Acquired Impaired Loans | Pass
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,704,311	1,614,595
Loans Excluding Acquired Impaired Loans | Pass | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	638,066	536,499
Loans Excluding Acquired Impaired Loans | Pass | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	398,743	419,880
Loans Excluding Acquired Impaired Loans | Pass | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	73,935	129,732
Loans Excluding Acquired Impaired Loans | Pass | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	415,163	369,136
Loans Excluding Acquired Impaired Loans | Pass | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	3,732	2,052
Loans Excluding Acquired Impaired Loans | Pass | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	174,672	157,296
Loans Excluding Acquired Impaired Loans | Watch
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	176,996	105,689
Loans Excluding Acquired Impaired Loans | Watch | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	58,217	38,707
Loans Excluding Acquired Impaired Loans | Watch | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	29,165	10,885
Loans Excluding Acquired Impaired Loans | Watch | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	22,380	2,897
Loans Excluding Acquired Impaired Loans | Watch | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	67,024	52,872
Loans Excluding Acquired Impaired Loans | Watch | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	20	4
Loans Excluding Acquired Impaired Loans | Watch | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	190	324
Loans Excluding Acquired Impaired Loans | Special Mention
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	34,892	11,422
Loans Excluding Acquired Impaired Loans | Special Mention | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	14,645	5,377
Loans Excluding Acquired Impaired Loans | Special Mention | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	2,251	3,116
Loans Excluding Acquired Impaired Loans | Special Mention | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	3,168	1,158
Loans Excluding Acquired Impaired Loans | Special Mention | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	13,535	1,258
Loans Excluding Acquired Impaired Loans | Special Mention | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases		1
Loans Excluding Acquired Impaired Loans | Special Mention | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,293	512
Loans Excluding Acquired Impaired Loans | Substandard
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	33,331	12,173
Loans Excluding Acquired Impaired Loans | Substandard | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	14,053	8,458
Loans Excluding Acquired Impaired Loans | Substandard | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	2,497	1,140
Loans Excluding Acquired Impaired Loans | Substandard | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	15,508	1,508
Loans Excluding Acquired Impaired Loans | Substandard | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	14	328
Loans Excluding Acquired Impaired Loans | Substandard | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,259	739
Loans Excluding Acquired Impaired Loans | Doubtful
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	272	95
Loans Excluding Acquired Impaired Loans | Doubtful | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	$ 272	$ 95

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+ 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

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