Portfolio Loans - Summary of Portfolio Loans Individually Evaluated for Impairment by Category (Details) - Non-Covered Loans - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	$ 24,343	$ 15,057
Recorded Investment With No Allowance	4,856	3,241
Recorded Investment With Allowance	10,831	12,150
Total Recorded Investment	15,687	15,391
Related Allowance	2,579	3,064
Average Recorded Investment	19,722	7,366
Commercial and industrial
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	20,750	12,341
Recorded Investment With No Allowance	2,321	566
Recorded Investment With Allowance	10,344	11,791
Total Recorded Investment	12,665	12,357
Related Allowance	2,508	2,909
Average Recorded Investment	16,270	4,489
CRE - investor owned
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	560	525
Recorded Investment With No Allowance	422	435
Recorded Investment With Allowance	0	0
Total Recorded Investment	422	435
Related Allowance	0	0
Average Recorded Investment	521	668
CRE - owner occupied
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	487	225
Recorded Investment With No Allowance	0	231
Recorded Investment With Allowance	487	0
Total Recorded Investment	487	231
Related Allowance	71	0
Average Recorded Investment	490	227
Construction and land development
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	441	1,904
Recorded Investment With No Allowance	136	1,947
Recorded Investment With Allowance	0	359
Total Recorded Investment	136	2,306
Related Allowance	0	155
Average Recorded Investment	331	1,918
Residential real estate
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	1,730	62
Recorded Investment With No Allowance	1,602	62
Recorded Investment With Allowance	0	0
Total Recorded Investment	1,602	62
Related Allowance	0	0
Average Recorded Investment	1,735	64
Consumer and other
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	375	0
Recorded Investment With No Allowance	375	0
Recorded Investment With Allowance	0	0
Total Recorded Investment	375	0
Related Allowance	0	0
Average Recorded Investment	$ 375	$ 0

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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

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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 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5258-111524

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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 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953550-111524

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