Loans - (Credit Exposure for Loans as Determined by Company's Internal Risk Rating System) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Loans [Line Items]
Total Loans	$ 2,738,504	$ 2,587,673	$ 2,328,524
Commercial Loan [Member]
Loans [Line Items]
Total Loans	1,490,749	1,427,420
Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	694,171	684,002
Consumer [Member]
Loans [Line Items]
Total Loans	27,845	33,366
Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	525,739	442,885
Non ASC 310-30 [Member]
Loans [Line Items]
Total Loans	2,569,222	2,384,843
Non ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	1,443,874	1,369,946
Non ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	674,830	662,550
Non ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	26,498	30,635
Non ASC 310-30 [Member] | Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	424,020	321,712
ASC 310-30 [Member]
Loans [Line Items]
Total Loans	169,282	202,830
ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	46,875	57,474
ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	19,341	21,452
ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	1,347	2,731
ASC 310-30 [Member] | Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	101,719	121,173
Total Loans [Member]
Loans [Line Items]
Total Loans	2,738,504	2,587,673
Total Loans [Member] | Non ASC 310-30 [Member]
Loans [Line Items]
Total Loans	2,569,222	2,384,843
Total Loans [Member] | Non ASC 310-30 [Member] | Commercial and Industrial [Member]
Loans [Line Items]
Total Loans	1,015,858	892,889
Total Loans [Member] | Non ASC 310-30 [Member] | Agriculture [Member]
Loans [Line Items]
Total Loans	131,685	145,558
Total Loans [Member] | Non ASC 310-30 [Member] | Energy Loans [Member]
Loans [Line Items]
Total Loans	104,663	146,880
Total Loans [Member] | Non ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	1,443,874	1,369,946
Total Loans [Member] | Non ASC 310-30 [Member] | Total Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	424,020	321,712
Total Loans [Member] | Non ASC 310-30 [Member] | Commercial Construction [Member]
Loans [Line Items]
Total Loans	83,136	30,143
Total Loans [Member] | Non ASC 310-30 [Member] | Commercial Acquisition/Development [Member]
Loans [Line Items]
Total Loans	8,763	5,575
Total Loans [Member] | Non ASC 310-30 [Member] | Multifamily [Member]
Loans [Line Items]
Total Loans	10,811	9,873
Total Loans [Member] | Non ASC 310-30 [Member] | Owner-Occupied [Member]
Loans [Line Items]
Total Loans	191,668	184,619
Total Loans [Member] | Non ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total Loans	321,310	276,121
Total Loans [Member] | Non ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	674,830	662,550
Total Loans [Member] | Non ASC 310-30 [Member] | Senior lien
Loans [Line Items]
Total Loans	620,757	614,493
Total Loans [Member] | Non ASC 310-30 [Member] | Junior lien
Loans [Line Items]
Total Loans	54,073	48,057
Total Loans [Member] | Non ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	26,498	30,635
Total Loans [Member] | ASC 310-30 [Member]
Loans [Line Items]
Total Loans	169,282	202,830
Total Loans [Member] | ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	46,875	57,474
Total Loans [Member] | ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	19,341	21,452
Total Loans [Member] | ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	1,347	2,731
Total Loans [Member] | ASC 310-30 [Member] | Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	101,719	121,173
Total Loans [Member] | Pass [Member]
Loans [Line Items]
Total Loans	2,532,072	2,356,761
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member]
Loans [Line Items]
Total Loans	2,441,376	2,252,304
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Commercial and Industrial [Member]
Loans [Line Items]
Total Loans	980,188	865,840
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Agriculture [Member]
Loans [Line Items]
Total Loans	128,721	132,450
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Energy Loans [Member]
Loans [Line Items]
Total Loans	59,603	92,152
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	1,340,812	1,264,550
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Total Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	406,381	301,638
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Commercial Construction [Member]
Loans [Line Items]
Total Loans	80,024	24,686
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Commercial Acquisition/Development [Member]
Loans [Line Items]
Total Loans	6,426	5,066
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Multifamily [Member]
Loans [Line Items]
Total Loans	10,811	9,851
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Owner-Occupied [Member]
Loans [Line Items]
Total Loans	172,300	174,108
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total Loans	309,120	262,035
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	667,986	655,633
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Senior lien
Loans [Line Items]
Total Loans	615,657	609,196
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Junior lien
Loans [Line Items]
Total Loans	52,329	46,437
Total Loans [Member] | Pass [Member] | Non ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	26,197	30,483
Total Loans [Member] | Pass [Member] | ASC 310-30 [Member]
Loans [Line Items]
Total Loans	90,696	104,457
Total Loans [Member] | Pass [Member] | ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	31,233	35,384
Total Loans [Member] | Pass [Member] | ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	15,396	16,960
Total Loans [Member] | Pass [Member] | ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	1,140	2,296
Total Loans [Member] | Pass [Member] | ASC 310-30 [Member] | Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	42,927	49,817
Total Loans [Member] | Special Mention [Member]
Loans [Line Items]
Total Loans	70,185	69,888
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member]
Loans [Line Items]
Total Loans	67,783	67,051
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Commercial and Industrial [Member]
Loans [Line Items]
Total Loans	23,574	8,363
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Agriculture [Member]
Loans [Line Items]
Total Loans	811	2,440
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Energy Loans [Member]
Loans [Line Items]
Total Loans	15,746	36,503
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	54,662	52,901
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Total Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	12,575	13,482
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Commercial Construction [Member]
Loans [Line Items]
Total Loans	2,731	4,882
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Commercial Acquisition/Development [Member]
Loans [Line Items]
Total Loans	2,337	509
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Owner-Occupied [Member]
Loans [Line Items]
Total Loans	14,531	5,595
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total Loans	7,507	8,091
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	484	601
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Senior lien
Loans [Line Items]
Total Loans	263	349
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Junior lien
Loans [Line Items]
Total Loans	221	252
Total Loans [Member] | Special Mention [Member] | Non ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	62	67
Total Loans [Member] | Special Mention [Member] | ASC 310-30 [Member]
Loans [Line Items]
Total Loans	2,402	2,837
Total Loans [Member] | Special Mention [Member] | ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	462	787
Total Loans [Member] | Special Mention [Member] | ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	1,574	1,604
Total Loans [Member] | Special Mention [Member] | ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	23	94
Total Loans [Member] | Special Mention [Member] | ASC 310-30 [Member] | Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	343	352
Total Loans [Member] | Substandard [Member]
Loans [Line Items]
Total Loans	117,549	152,911
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member]
Loans [Line Items]
Total Loans	45,134	61,144
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Commercial and Industrial [Member]
Loans [Line Items]
Total Loans	9,893	16,769
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Agriculture [Member]
Loans [Line Items]
Total Loans	2,153	10,668
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Energy Loans [Member]
Loans [Line Items]
Total Loans	16,588	16,098
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	33,471	48,451
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Total Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	5,064	6,319
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Commercial Construction [Member]
Loans [Line Items]
Total Loans	381	575
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Multifamily [Member]
Loans [Line Items]
Total Loans		22
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Owner-Occupied [Member]
Loans [Line Items]
Total Loans	4,837	4,916
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total Loans	4,683	5,722
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	6,360	6,289
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Senior lien
Loans [Line Items]
Total Loans	4,837	4,921
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Junior lien
Loans [Line Items]
Total Loans	1,523	1,368
Total Loans [Member] | Substandard [Member] | Non ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	239	85
Total Loans [Member] | Substandard [Member] | ASC 310-30 [Member]
Loans [Line Items]
Total Loans	72,415	91,767
Total Loans [Member] | Substandard [Member] | ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	15,180	21,303
Total Loans [Member] | Substandard [Member] | ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total Loans	2,371	2,888
Total Loans [Member] | Substandard [Member] | ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total Loans	184	341
Total Loans [Member] | Substandard [Member] | ASC 310-30 [Member] | Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	54,680	67,235
Total Loans [Member] | Doubtful [Member]
Loans [Line Items]
Total Loans	18,698	8,113
Total Loans [Member] | Doubtful [Member] | Non ASC 310-30 [Member]
Loans [Line Items]
Total Loans	14,929	4,344
Total Loans [Member] | Doubtful [Member] | Non ASC 310-30 [Member] | Commercial and Industrial [Member]
Loans [Line Items]
Total Loans	2,203	1,917
Total Loans [Member] | Doubtful [Member] | Non ASC 310-30 [Member] | Energy Loans [Member]
Loans [Line Items]
Total Loans	12,726	2,127
Total Loans [Member] | Doubtful [Member] | Non ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total Loans	14,929	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		27
Total Loans [Member] | Doubtful [Member] | Non ASC 310-30 [Member] | Senior lien
Loans [Line Items]
Total Loans		27
Total Loans [Member] | Doubtful [Member] | ASC 310-30 [Member]
Loans [Line Items]
Total Loans	3,769	3,769
Total Loans [Member] | Doubtful [Member] | ASC 310-30 [Member] | Commercial Real Estate [Member]
Loans [Line Items]
Total Loans	$ 3,769	$ 3,769