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Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Allowance for Loan and Lease Losses and Corresponding Loan and Lease Balances (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | ---
Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Allowance for loan and lease losses |  |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance |  |  |  | $ 10,923 |  |  |  | $ 7,632 | $ 10,923 | $ 7,632 | $ 4,794 |  |  |
Provisions | $ 3,347 | $ 3,900 | $ 3,515 | 1,891 | $ 5,004 | $ 1,683 | $ 1,152 | 2,513 | 12,653 | 10,352 | 6,966 |  |  |
Charge-offs |  |  |  |  |  |  |  |  | (8,196) | (7,817) | (4,359) |  |  |
Recoveries |  |  |  |  |  |  |  |  | 1,326 | 756 | 231 |  |  |
Ending balance | 16,706 |  |  |  | 10,923 |  |  |  | 16,706 | 10,923 | 7,632 |  |  |
Ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | $ 3,965 | $ 1,017 | $ 2,326
Collectively evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 8,867 | 8,295 | 2,016
Allowance for loan and lease losses | 16,706 |  |  | 10,923 | 10,923 |  |  | 7,632 | 16,706 | 10,923 | 7,632 | 16,706 | 10,923 | 7,632
Loans and leases ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 31,111 | 11,926 | 8,908
Collectively evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 1,918,691 | 1,732,048 | 849,618
Total loans and leases |  |  |  |  |  |  |  |  |  |  |  | 2,277,492 | 2,148,011 | 1,345,437
Receivables Acquired with Deteriorated Credit Quality |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loans acquired with deteriorated credit quality |  |  |  |  |  |  |  |  |  |  |  | 3,874 | 1,611 | 3,290
Loans and leases ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loans acquired with deteriorated credit quality |  |  |  |  |  |  |  |  |  |  |  | 327,690 | 404,037 | 486,911
Commercial Real Estate |  |  |  |  |  |  |  |  |  |  |  |  |  |
Allowance for loan and lease losses |  |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance |  |  |  | 1,945 |  |  |  | 2,280 | 1,945 | 2,280 | 1,112 |  |  |
Provisions |  |  |  |  |  |  |  |  | 4,343 | 4,032 | 2,464 |  |  |
Charge-offs |  |  |  |  |  |  |  |  | (1,494) | (4,367) | (1,296) |  |  |
Ending balance | 4,794 |  |  |  | 1,945 |  |  |  | 4,794 | 1,945 | 2,280 |  |  |
Ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 1,101 |  | 1,076
Collectively evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 1,765 | 1,456 | 470
Allowance for loan and lease losses | 4,794 |  |  | 1,945 | 1,945 |  |  | 2,280 | 1,945 | 1,945 | 2,280 | 4,794 | 1,945 | 2,280
Loans and leases ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 13,884 | 8,916 | 4,160
Collectively evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 711,097 | 580,125 | 285,571
Total loans and leases |  |  |  |  |  |  |  |  |  |  |  | 891,693 | 796,344 | 533,695
Commercial Real Estate | Receivables Acquired with Deteriorated Credit Quality |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loans acquired with deteriorated credit quality |  |  |  |  |  |  |  |  |  |  |  | 1,928 | 489 | 734
Loans and leases ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loans acquired with deteriorated credit quality |  |  |  |  |  |  |  |  |  |  |  | 166,712 | 207,303 | 243,964
Residential Real Estate |  |  |  |  |  |  |  |  |  |  |  |  |  |
Allowance for loan and lease losses |  |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance |  |  |  | 2,483 |  |  |  | 2,981 | 2,483 | 2,981 | 1,936 |  |  |
Provisions |  |  |  |  |  |  |  |  | (405) | 135 | 1,873 |  |  |
Charge-offs |  |  |  |  |  |  |  |  | (440) | (633) | (828) |  |  |
Ending balance | 1,638 |  |  |  | 2,483 |  |  |  | 1,638 | 2,483 | 2,981 |  |  |
Ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 158 | 293 | 615
Collectively evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 1,047 | 1,743 | 476
Allowance for loan and lease losses | 1,638 |  |  | 2,483 | 2,483 |  |  | 2,981 | 2,483 | 2,483 | 2,981 | 1,638 | 2,483 | 2,981
Loans and leases ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 2,429 | 1,300 | 4,042
Collectively evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 430,227 | 433,721 | 256,555
Total loans and leases |  |  |  |  |  |  |  |  |  |  |  | 577,218 | 610,738 | 484,335
Residential Real Estate | Receivables Acquired with Deteriorated Credit Quality |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loans acquired with deteriorated credit quality |  |  |  |  |  |  |  |  |  |  |  | 433 | 447 | 1,890
Loans and leases ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loans acquired with deteriorated credit quality |  |  |  |  |  |  |  |  |  |  |  | 144,562 | 175,717 | 223,738
Construction, Land Development, and Other Land |  |  |  |  |  |  |  |  |  |  |  |  |  |
Allowance for loan and lease losses |  |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance |  |  |  | 742 |  |  |  | 232 | 742 | 232 | 834 |  |  |
Provisions |  |  |  |  |  |  |  |  | (520) | 605 | (585) |  |  |
Charge-offs |  |  |  |  |  |  |  |  |  | (95) | (17) |  |  |
Ending balance | 222 |  |  |  | 742 |  |  |  | 222 | 742 | 232 |  |  |
Ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  |  |  | 137
Collectively evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 145 | 742 | 95
Allowance for loan and lease losses | 222 |  |  | 742 | 742 |  |  | 232 | 742 | 742 | 232 | 222 | 742 | 232
Loans and leases ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  |  |  | 208
Collectively evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 99,483 | 133,787 | 31,390
Total loans and leases |  |  |  |  |  |  |  |  |  |  |  | 105,429 | 140,766 | 40,232
Construction, Land Development, and Other Land | Receivables Acquired with Deteriorated Credit Quality |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loans acquired with deteriorated credit quality |  |  |  |  |  |  |  |  |  |  |  | 77 |  |
Loans and leases ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loans acquired with deteriorated credit quality |  |  |  |  |  |  |  |  |  |  |  | 5,946 | 6,979 | 8,634
Commercial and Industrial |  |  |  |  |  |  |  |  |  |  |  |  |  |
Allowance for loan and lease losses |  |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance |  |  |  | 4,196 |  |  |  | 1,403 | 4,196 | 1,403 | 648 |  |  |
Provisions |  |  |  |  |  |  |  |  | 6,058 | 2,869 | 782 |  |  |
Charge-offs |  |  |  |  |  |  |  |  | (2,836) | (76) | (30) |  |  |
Recoveries |  |  |  |  |  |  |  |  |  |  | 3 |  |  |
Ending balance | 7,418 |  |  |  | 4,196 |  |  |  | 7,418 | 4,196 | 1,403 |  |  |
Ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 2,692 | 396 | 171
Collectively evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 3,308 | 3,126 | 596
Allowance for loan and lease losses | 7,418 |  |  | 4,196 | 4,196 |  |  | 1,403 | 4,196 | 4,196 | 1,403 | 7,418 | 4,196 | 1,403
Loans and leases ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 14,784 | 1,382 | 171
Collectively evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 496,446 | 423,392 | 155,955
Total loans and leases |  |  |  |  |  |  |  |  |  |  |  | 521,238 | 438,238 | 165,696
Commercial and Industrial | Receivables Acquired with Deteriorated Credit Quality |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loans acquired with deteriorated credit quality |  |  |  |  |  |  |  |  |  |  |  | 1,418 | 674 | 636
Loans and leases ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loans acquired with deteriorated credit quality |  |  |  |  |  |  |  |  |  |  |  | 10,008 | 13,464 | 9,570
Installment and Other |  |  |  |  |  |  |  |  |  |  |  |  |  |
Allowance for loan and lease losses |  |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance |  |  |  | 334 |  |  |  | 357 | 334 | 357 | 121 |  |  |
Provisions |  |  |  |  |  |  |  |  | 34 | (11) | 237 |  |  |
Charge-offs |  |  |  |  |  |  |  |  | (327) | (12) | (1) |  |  |
Ending balance | 41 |  |  |  | 334 |  |  |  | 41 | 334 | 357 |  |  |
Ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 14 | 328 | 327
Collectively evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 9 | 5 |
Allowance for loan and lease losses | 41 |  |  | 334 | 334 |  |  | 357 | 334 | 334 | 357 | 41 | 334 | 357
Loans and leases ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 14 | 328 | 327
Collectively evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 3,752 | 2,057 | 594
Total loans and leases |  |  |  |  |  |  |  |  |  |  |  | 4,228 | 2,959 | 1,926
Installment and Other | Receivables Acquired with Deteriorated Credit Quality |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loans acquired with deteriorated credit quality |  |  |  |  |  |  |  |  |  |  |  | 18 | 1 | 30
Loans and leases ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loans acquired with deteriorated credit quality |  |  |  |  |  |  |  |  |  |  |  | 462 | 574 | 1,005
Lease Financing Receivables |  |  |  |  |  |  |  |  |  |  |  |  |  |
Allowance for loan and lease losses |  |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance |  |  |  | 1,223 |  |  |  | 379 | 1,223 | 379 | 143 |  |  |
Provisions |  |  |  |  |  |  |  |  | 3,143 | 2,722 | 2,195 |  |  |
Charge-offs |  |  |  |  |  |  |  |  | (3,099) | (2,634) | (2,187) |  |  |
Recoveries |  |  |  |  |  |  |  |  | 1,326 | 756 | 228 |  |  |
Ending balance | 2,593 |  |  |  | 1,223 |  |  |  | 2,593 | 1,223 | 379 |  |  |
Ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Collectively evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 2,593 | 1,223 | 379
Allowance for loan and lease losses | $ 2,593 |  |  | $ 1,223 | $ 1,223 |  |  | $ 379 | $ 1,223 | $ 1,223 | $ 379 | 2,593 | 1,223 | 379
Loans and leases ending balance: |  |  |  |  |  |  |  |  |  |  |  |  |  |
Collectively evaluated for impairment |  |  |  |  |  |  |  |  |  |  |  | 177,686 | 158,966 | 119,553
Total loans and leases |  |  |  |  |  |  |  |  |  |  |  | $ 177,686 | $ 158,966 | $ 119,553

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- Definition A valuation allowance for financing receivables that are expected to be uncollectible. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 + Details
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- Definition The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 + Details
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- Definition The balance of financing receivables that were collectively evaluated for impairment. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 + Details
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- Definition Net amount of the investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, credit card receivables, notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets. Excludes trade accounts receivable with contractual maturity of one year or less and arose from the sale of goods or services. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.3) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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