Loans - Loans Portfolio by Internal Risk Grading (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 1,836,241	$ 1,357,476	[1]
Commercial
Financing Receivable, Recorded Investment [Line Items]
Total loans	340,427	285,972
Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,033,022	753,040
Commercial real estate | Construction and land development
Financing Receivable, Recorded Investment [Line Items]
Total loans	152,876	97,240
Commercial real estate | Other
Financing Receivable, Recorded Investment [Line Items]
Total loans	880,146	655,800
Commercial real estate | Real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans	880,146	655,800
Residential
Financing Receivable, Recorded Investment [Line Items]
Total loans	450,305	313,371
Residential | Real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans	328,400	209,438
Residential | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	121,905	103,933
Consumer
Financing Receivable, Recorded Investment [Line Items]
Total loans	12,487	5,093
Consumer | Performing
Financing Receivable, Recorded Investment [Line Items]
Total loans	12,487	5,093
Consumer | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Pass | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total loans	327,393	285,092
Pass | Commercial real estate | Construction and land development
Financing Receivable, Recorded Investment [Line Items]
Total loans	146,539	93,000
Pass | Commercial real estate | Other
Financing Receivable, Recorded Investment [Line Items]
Total loans	835,625	647,519
Pass | Residential | Real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans	315,392	204,261
Pass | Residential | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	121,511	103,541
Special Mention | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total loans	11,295	154
Special Mention | Commercial real estate | Construction and land development
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,993	1,840
Special Mention | Commercial real estate | Other
Financing Receivable, Recorded Investment [Line Items]
Total loans	32,446	4,403
Special Mention | Residential | Real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans	7,782	1,685
Special Mention | Residential | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Substandard | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,739	726
Substandard | Commercial real estate | Construction and land development
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,344	2,400
Substandard | Commercial real estate | Other
Financing Receivable, Recorded Investment [Line Items]
Total loans	12,075	3,878
Substandard | Residential | Real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,226	3,492
Substandard | Residential | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	394	392
Doubtful | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Doubtful | Commercial real estate | Construction and land development
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Doubtful | Commercial real estate | Other
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Doubtful | Residential | Real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Doubtful | Residential | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 0	$ 0

[1] Derived from audited consolidated financial statements.