Loans - Summary of Loan Classifications by Class of Loan (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Summary of loan classifications by class of loan [Abstract]
Unearned income	$ (3,017)	$ (2,382)
Total Loans	1,969,660	1,049,698	$ 966,545
Pass
Summary of loan classifications by class of loan [Abstract]
Total Loans	1,940,514	1,020,905
Special Mention
Summary of loan classifications by class of loan [Abstract]
Total Loans	10,322	6,989
Substandard
Summary of loan classifications by class of loan [Abstract]
Total Loans	21,651	24,186
Doubtful
Summary of loan classifications by class of loan [Abstract]
Total Loans	190	0
Loss
Summary of loan classifications by class of loan [Abstract]
Total Loans	0	0
Real estate construction
Summary of loan classifications by class of loan [Abstract]
Unearned income	(415)	(414)
Total Loans	104,193	91,822	79,621
Real estate construction | Pass
Summary of loan classifications by class of loan [Abstract]
Total Loans	98,263	91,296
Real estate construction | Special Mention
Summary of loan classifications by class of loan [Abstract]
Total Loans	5,419	0
Real estate construction | Substandard
Summary of loan classifications by class of loan [Abstract]
Total Loans	926	940
Real estate construction | Doubtful
Summary of loan classifications by class of loan [Abstract]
Total Loans	0	0
Real estate construction | Loss
Summary of loan classifications by class of loan [Abstract]
Total Loans	0	0
Commercial real estate - owner occupied
Summary of loan classifications by class of loan [Abstract]
Unearned income	(705)	(581)
Total Loans	443,128	250,440	238,224
Commercial real estate - owner occupied | Pass
Summary of loan classifications by class of loan [Abstract]
Total Loans	438,924	247,001
Commercial real estate - owner occupied | Special Mention
Summary of loan classifications by class of loan [Abstract]
Total Loans	1,452	1,213
Commercial real estate - owner occupied | Substandard
Summary of loan classifications by class of loan [Abstract]
Total Loans	3,457	2,807
Commercial real estate - owner occupied | Doubtful
Summary of loan classifications by class of loan [Abstract]
Total Loans	0	0
Commercial real estate - owner occupied | Loss
Summary of loan classifications by class of loan [Abstract]
Total Loans	0	0
Commercial real estate - nonowner occupied
Summary of loan classifications by class of loan [Abstract]
Unearned income	(1,001)	(632)
Total Loans	435,181	184,688	174,342
Commercial real estate - nonowner occupied | Pass
Summary of loan classifications by class of loan [Abstract]
Total Loans	434,911	185,020
Commercial real estate - nonowner occupied | Special Mention
Summary of loan classifications by class of loan [Abstract]
Total Loans	284	300
Commercial real estate - nonowner occupied | Substandard
Summary of loan classifications by class of loan [Abstract]
Total Loans	987	0
Commercial real estate - nonowner occupied | Doubtful
Summary of loan classifications by class of loan [Abstract]
Total Loans	0	0
Commercial real estate - nonowner occupied | Loss
Summary of loan classifications by class of loan [Abstract]
Total Loans	0	0
Residential real estate
Summary of loan classifications by class of loan [Abstract]
Unearned income	(171)	(159)
Total Loans	512,621	204,413	202,605
Residential real estate | Pass
Summary of loan classifications by class of loan [Abstract]
Total Loans	509,478	202,762
Residential real estate | Special Mention
Summary of loan classifications by class of loan [Abstract]
Total Loans	647	932
Residential real estate | Substandard
Summary of loan classifications by class of loan [Abstract]
Total Loans	2,667	878
Residential real estate | Doubtful
Summary of loan classifications by class of loan [Abstract]
Total Loans	0	0
Residential real estate | Loss
Summary of loan classifications by class of loan [Abstract]
Total Loans	0	0
Commercial
Summary of loan classifications by class of loan [Abstract]
Unearned income	(729)	(597)
Total Loans	449,450	311,486	264,794
Commercial | Pass
Summary of loan classifications by class of loan [Abstract]
Total Loans	433,861	287,978
Commercial | Special Mention
Summary of loan classifications by class of loan [Abstract]
Total Loans	2,520	4,544
Commercial | Substandard
Summary of loan classifications by class of loan [Abstract]
Total Loans	13,611	19,561
Commercial | Doubtful
Summary of loan classifications by class of loan [Abstract]
Total Loans	187	0
Commercial | Loss
Summary of loan classifications by class of loan [Abstract]
Total Loans	0	0
Consumer
Summary of loan classifications by class of loan [Abstract]
Unearned income	4	1
Total Loans	25,087	6,849	$ 6,959
Consumer | Pass
Summary of loan classifications by class of loan [Abstract]
Total Loans	25,077	6,848
Consumer | Special Mention
Summary of loan classifications by class of loan [Abstract]
Total Loans	0	0
Consumer | Substandard
Summary of loan classifications by class of loan [Abstract]
Total Loans	3	0
Consumer | Doubtful
Summary of loan classifications by class of loan [Abstract]
Total Loans	3	0
Consumer | Loss
Summary of loan classifications by class of loan [Abstract]
Total Loans	$ 0	$ 0