Loans - (Credit Exposure for Loans as Determined by Company's Internal Risk Rating System) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Loans [Line Items]
Total Loans	$ 2,860,921	$ 2,587,673
Commercial Loan [Member]
Loans [Line Items]
Total Loans	1,560,430	1,427,420
Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	744,885	684,002
Consumer [Member]
Loans [Line Items]
Total Loans	28,814	33,366
Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	526,792	442,885
Non ASC 310-30 [Member]
Loans [Line Items]
Total Loans	2,715,069	2,384,843
Non ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	1,521,150	1,369,946
Non ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	728,361	662,550
Non ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	27,916	30,635
Non ASC 310-30 [Member] | Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	437,642	321,712
ASC 310-30 [Member]
Loans [Line Items]
Total Loans	145,852	202,830
ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	39,280	57,474
ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	16,524	21,452
ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	898	2,731
ASC 310-30 [Member] | Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	89,150	121,173
Total Loans [Member]
Loans [Line Items]
Total Loans	2,860,921	2,587,673
Total Loans [Member] | Non ASC 310-30 [Member]
Loans [Line Items]
Total Loans	2,715,069	2,384,843
Total Loans [Member] | Non ASC 310-30 [Member] | Commercial and Industrial [Member]
Loans [Line Items]
Total Loans	1,074,696	892,889
Total Loans [Member] | Non ASC 310-30 [Member] | Agriculture [Member]
Loans [Line Items]
Total Loans	134,637	145,558
Total Loans [Member] | Non ASC 310-30 [Member] | Energy Loans [Member]
Loans [Line Items]
Total Loans	90,273	146,880
Total Loans [Member] | Non ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	1,521,150	1,369,946
Total Loans [Member] | Non ASC 310-30 [Member] | Total Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	437,642	321,712
Total Loans [Member] | Non ASC 310-30 [Member] | Commercial Construction [Member]
Loans [Line Items]
Total Loans	90,314	30,143
Total Loans [Member] | Non ASC 310-30 [Member] | Commercial Acquisition/Development [Member]
Loans [Line Items]
Total Loans	13,306	5,575
Total Loans [Member] | Non ASC 310-30 [Member] | Multifamily [Member]
Loans [Line Items]
Total Loans	24,954	9,873
Total Loans [Member] | Non ASC 310-30 [Member] | Owner-Occupied [Member]
Loans [Line Items]
Total Loans	221,544	184,619
Total Loans [Member] | Non ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total Loans	309,068	276,121
Total Loans [Member] | Non ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	728,361	662,550
Total Loans [Member] | Non ASC 310-30 [Member] | Senior lien
Loans [Line Items]
Total Loans	675,690	614,493
Total Loans [Member] | Non ASC 310-30 [Member] | Junior lien
Loans [Line Items]
Total Loans	52,671	48,057
Total Loans [Member] | Non ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	27,916	30,635
Total Loans [Member] | ASC 310-30 [Member]
Loans [Line Items]
Total Loans	145,852	202,830
Total Loans [Member] | ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	39,280	57,474
Total Loans [Member] | ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total Loans	89,150	121,173
Total Loans [Member] | ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	16,524	21,452
Total Loans [Member] | ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	898	2,731
Total Loans [Member] | Pass [Member]
Loans [Line Items]
Total Loans	2,696,660	2,356,761
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member]
Loans [Line Items]
Total Loans	2,617,131	2,252,304
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Commercial and Industrial [Member]
Loans [Line Items]
Total Loans	1,041,326	865,840
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Agriculture [Member]
Loans [Line Items]
Total Loans	123,809	132,450
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Energy Loans [Member]
Loans [Line Items]
Total Loans	77,619	92,152
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	1,444,790	1,264,550
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Total Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	424,274	301,638
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Commercial Construction [Member]
Loans [Line Items]
Total Loans	90,099	24,686
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Commercial Acquisition/Development [Member]
Loans [Line Items]
Total Loans	10,758	5,066
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Multifamily [Member]
Loans [Line Items]
Total Loans	22,495	9,851
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Owner-Occupied [Member]
Loans [Line Items]
Total Loans	202,036	174,108
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total Loans	300,922	262,035
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	720,398	655,633
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Senior lien
Loans [Line Items]
Total Loans	669,148	609,196
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Junior lien
Loans [Line Items]
Total Loans	51,250	46,437
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	27,669	30,483
Total Loans [Member] | Pass [Member] | ASC 310-30 [Member]
Loans [Line Items]
Total Loans	79,529	104,457
Total Loans [Member] | Pass [Member] | ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	27,436	35,384
Total Loans [Member] | Pass [Member] | ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total Loans	38,895	49,817
Total Loans [Member] | Pass [Member] | ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	12,477	16,960
Total Loans [Member] | Pass [Member] | ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	721	2,296
Total Loans [Member] | Special Mention [Member]
Loans [Line Items]
Total Loans	38,590	69,888
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member]
Loans [Line Items]
Total Loans	35,669	67,051
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Commercial and Industrial [Member]
Loans [Line Items]
Total Loans	7,243	8,363
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Agriculture [Member]
Loans [Line Items]
Total Loans	8,922	2,440
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Energy Loans [Member]
Loans [Line Items]
Total Loans		36,503
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	25,536	52,901
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Total Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	8,681	13,482
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Commercial Construction [Member]
Loans [Line Items]
Total Loans		4,882
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Commercial Acquisition/Development [Member]
Loans [Line Items]
Total Loans	2,548	509
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Multifamily [Member]
Loans [Line Items]
Total Loans	238
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Owner-Occupied [Member]
Loans [Line Items]
Total Loans	9,371	5,595
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total Loans	5,895	8,091
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	1,393	601
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Senior lien
Loans [Line Items]
Total Loans	1,215	349
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Junior lien
Loans [Line Items]
Total Loans	178	252
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	59	67
Total Loans [Member] | Special Mention [Member] | ASC 310-30 [Member]
Loans [Line Items]
Total Loans	2,921	2,837
Total Loans [Member] | Special Mention [Member] | ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	610	787
Total Loans [Member] | Special Mention [Member] | ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total Loans	967	352
Total Loans [Member] | Special Mention [Member] | ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	1,327	1,604
Total Loans [Member] | Special Mention [Member] | ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	17	94
Total Loans [Member] | Substandard [Member]
Loans [Line Items]
Total Loans	116,558	152,911
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member]
Loans [Line Items]
Total Loans	56,924	61,144
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Commercial and Industrial [Member]
Loans [Line Items]
Total Loans	25,636	16,769
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Agriculture [Member]
Loans [Line Items]
Total Loans	1,906	10,668
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Energy Loans [Member]
Loans [Line Items]
Total Loans	7,811	16,098
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	45,490	48,451
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Total Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	4,687	6,319
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Commercial Construction [Member]
Loans [Line Items]
Total Loans	215	575
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Multifamily [Member]
Loans [Line Items]
Total Loans	2,221	22
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Owner-Occupied [Member]
Loans [Line Items]
Total Loans	10,137	4,916
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total Loans	2,251	5,722
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	6,559	6,289
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Senior lien
Loans [Line Items]
Total Loans	5,316	4,921
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Junior lien
Loans [Line Items]
Total Loans	1,243	1,368
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	188	85
Total Loans [Member] | Substandard [Member] | ASC 310-30 [Member]
Loans [Line Items]
Total Loans	59,634	91,767
Total Loans [Member] | Substandard [Member] | ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	11,234	21,303
Total Loans [Member] | Substandard [Member] | ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total Loans	45,520	67,235
Total Loans [Member] | Substandard [Member] | ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	2,720	2,888
Total Loans [Member] | Substandard [Member] | ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	160	341
Total Loans [Member] | Doubtful [Member]
Loans [Line Items]
Total Loans	9,113	8,113
Total Loans [Member] | Doubtful [Member] | Non ASC 310-30 [Member]
Loans [Line Items]
Total Loans	5,345	4,344
Total Loans [Member] | Doubtful [Member] | Non ASC 310-30 [Member] | Commercial and Industrial [Member]
Loans [Line Items]
Total Loans	491	1,917
Total Loans [Member] | Doubtful [Member] | Non ASC 310-30 [Member] | Energy Loans [Member]
Loans [Line Items]
Total Loans	4,843	2,127
Total Loans [Member] | Doubtful [Member] | Non ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	5,334	4,044
Total Loans [Member] | Doubtful [Member] | Non ASC 310-30 [Member] | Total Commercial Real Estate [Member]
Loans [Line Items]
Total Loans		273
Total Loans [Member] | Doubtful [Member] | Non ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total Loans		273
Total Loans [Member] | Doubtful [Member] | Non ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	11	27
Total Loans [Member] | Doubtful [Member] | Non ASC 310-30 [Member] | Senior lien
Loans [Line Items]
Total Loans	11	27
Total Loans [Member] | Doubtful [Member] | ASC 310-30 [Member]
Loans [Line Items]
Total Loans	3,768	3,769
Total Loans [Member] | Doubtful [Member] | ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total Loans	$ 3,768	$ 3,769