Loans - Credit Quality (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loans by risk rating
Total Loans	$ 1,478,809	$ 1,133,715	$ 1,159,332
Commercial
Loans by risk rating
Total Loans	283,564	141,315	127,196
Real estate - commercial
Loans by risk rating
Total Loans	736,247	605,721	600,629
Real estate - commercial | Owner occupied general purpose
Loans by risk rating
Total Loans	137,236	125,504
Real estate - commercial | Owner occupied special purpose
Loans by risk rating
Total Loans	178,140	171,948
Real estate - commercial | Non-owner occupied general purpose
Loans by risk rating
Total Loans	232,291	167,643
Real estate - commercial | Non-owner occupied special purpose
Loans by risk rating
Total Loans	119,065	92,387
Real estate - commercial | Retail properties
Loans by risk rating
Total Loans	54,653	34,352
Real estate - commercial | Farm
Loans by risk rating
Total Loans	14,862	13,887
Real estate - residential
Loans by risk rating
Total Loans	377,851	351,007	370,191
Real estate - residential | Investor
Loans by risk rating
Total Loans	152,599	126,684
Real estate - residential | Owner occupied
Loans by risk rating
Total Loans	123,626	118,792
Real estate - residential | Revolving and junior liens
Loans by risk rating
Total Loans	101,626	105,531
Consumer
Loans by risk rating
Total Loans	3,237	4,216	3,504
All other
Loans by risk rating
Total Loans	13,190	11,650	13,017
Pass
Loans by risk rating
Total Loans	1,430,321	1,101,886
Pass | Commercial
Loans by risk rating
Total Loans	267,394	136,078
Pass | Real estate - commercial | Owner occupied general purpose
Loans by risk rating
Total Loans	135,503	123,827
Pass | Real estate - commercial | Owner occupied special purpose
Loans by risk rating
Total Loans	172,353	171,185
Pass | Real estate - commercial | Non-owner occupied general purpose
Loans by risk rating
Total Loans	229,448	163,956
Pass | Real estate - commercial | Non-owner occupied special purpose
Loans by risk rating
Total Loans	114,293	88,468
Pass | Real estate - commercial | Retail properties
Loans by risk rating
Total Loans	52,207	30,432
Pass | Real estate - commercial | Farm
Loans by risk rating
Total Loans	11,840	12,615
Pass | Real estate - residential | Investor
Loans by risk rating
Total Loans	151,503	125,548
Pass | Real estate - residential | Owner occupied
Loans by risk rating
Total Loans	115,831	111,713
Pass | Real estate - residential | Revolving and junior liens
Loans by risk rating
Total Loans	99,286	102,476
Pass | Consumer
Loans by risk rating
Total Loans	3,236	4,215
Pass | All other
Loans by risk rating
Total Loans	13,165	11,650
Special Mention
Loans by risk rating
Total Loans	22,004	6,606
Special Mention | Commercial
Loans by risk rating
Total Loans	12,534	3,208
Special Mention | Real estate - commercial | Owner occupied general purpose
Loans by risk rating
Total Loans	53
Special Mention | Real estate - commercial | Owner occupied special purpose
Loans by risk rating
Total Loans	5,402
Special Mention | Real estate - commercial | Non-owner occupied general purpose
Loans by risk rating
Total Loans	913	1,908
Special Mention | Real estate - commercial | Retail properties
Loans by risk rating
Total Loans	1,267	1,490
Special Mention | Real estate - commercial | Farm
Loans by risk rating
Total Loans	1,240
Special Mention | Real estate - residential | Owner occupied
Loans by risk rating
Total Loans	570
Special Mention | All other
Loans by risk rating
Total Loans	25
Substandard
Loans by risk rating
Total Loans	26,484	25,223
Substandard | Commercial
Loans by risk rating
Total Loans	3,636	2,029
Substandard | Real estate - commercial | Owner occupied general purpose
Loans by risk rating
Total Loans	1,680	1,677
Substandard | Real estate - commercial | Owner occupied special purpose
Loans by risk rating
Total Loans	385	763
Substandard | Real estate - commercial | Non-owner occupied general purpose
Loans by risk rating
Total Loans	1,930	1,779
Substandard | Real estate - commercial | Non-owner occupied special purpose
Loans by risk rating
Total Loans	4,772	3,919
Substandard | Real estate - commercial | Retail properties
Loans by risk rating
Total Loans	1,179	2,430
Substandard | Real estate - commercial | Farm
Loans by risk rating
Total Loans	1,782	1,272
Substandard | Real estate - residential | Investor
Loans by risk rating
Total Loans	1,096	1,136
Substandard | Real estate - residential | Owner occupied
Loans by risk rating
Total Loans	7,225	7,079
Substandard | Real estate - residential | Revolving and junior liens
Loans by risk rating
Total Loans	2,340	3,055
Substandard | Consumer
Loans by risk rating
Total Loans	1	1
Construction Loans | Real estate - commercial
Loans by risk rating
Total Loans	64,720	19,806	$ 44,795
Construction Loans | Real estate - commercial | Homebuilder
Loans by risk rating
Total Loans	3,883	2,604
Construction Loans | Real estate - commercial | Land
Loans by risk rating
Total Loans	3,029	1,137
Construction Loans | Real estate - commercial | Commercial speculative
Loans by risk rating
Total Loans	22,728	2,200
Construction Loans | Real estate - commercial | All other
Loans by risk rating
Total Loans	35,080	13,865
Construction Loans | Pass | Real estate - commercial | Homebuilder
Loans by risk rating
Total Loans	3,883	2,604
Construction Loans | Pass | Real estate - commercial | Land
Loans by risk rating
Total Loans	3,029	1,137
Construction Loans | Pass | Real estate - commercial | Commercial speculative
Loans by risk rating
Total Loans	22,654	2,117
Construction Loans | Pass | Real estate - commercial | All other
Loans by risk rating
Total Loans	34,696	13,865
Construction Loans | Substandard | Real estate - commercial | Commercial speculative
Loans by risk rating
Total Loans	74	$ 83
Construction Loans | Substandard | Real estate - commercial | All other
Loans by risk rating
Total Loans	$ 384