Loans - (Loan Delinquency) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Loans [Line Items]
Total loans	$ 2,953,655	$ 2,860,921	$ 2,592,047
Commercial Loan [Member]
Loans [Line Items]
Total loans	1,641,596	1,560,430
Commercial Real Estate [Member]
Loans [Line Items]
Total loans	537,993	526,792
Residential Real Estate Segment [Member]
Loans [Line Items]
Total loans	746,455	744,885
Consumer [Member]
Loans [Line Items]
Total loans	27,611	28,814
Non ASC 310-30 [Member]
Loans [Line Items]
Total loans	2,813,591	2,715,069
Non ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total loans	1,604,661	1,521,150
Non ASC 310-30 [Member] | Commercial Real Estate [Member]
Loans [Line Items]
Total loans	451,151	437,642
Non ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total loans	730,985	728,361
Non ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total loans	26,794	27,916
ASC 310-30 [Member]
Loans [Line Items]
Total loans	140,064	145,852	$ 179,507
ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total loans	36,935	39,280
ASC 310-30 [Member] | Commercial Real Estate [Member]
Loans [Line Items]
Total loans	86,842	89,150
ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total loans	15,470	16,524
ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total loans	817	898
Total Loans [Member]
Loans [Line Items]
Total loans	2,953,655	2,860,921
Total Loans [Member] | Non ASC 310-30 [Member]
Loans [Line Items]
Total past due loans	25,576	19,435
Current	2,788,015	2,695,634
Total loans	2,813,591	2,715,069
Loans 90 days past due and still accruing	105
Non- accrual	33,716	30,717
Total Loans [Member] | Non ASC 310-30 [Member] | Commercial Construction [Member]
Loans [Line Items]
Total past due loans	215
Current	115,288	90,314
Total loans	115,503	90,314
Total Loans [Member] | Non ASC 310-30 [Member] | Commercial Acquisition/Development [Member]
Loans [Line Items]
Current	15,577	13,306
Total loans	15,577	13,306
Total Loans [Member] | Non ASC 310-30 [Member] | Multifamily [Member]
Loans [Line Items]
Current	25,278	24,954
Total loans	25,278	24,954
Total Loans [Member] | Non ASC 310-30 [Member] | Commercial and Industrial [Member]
Loans [Line Items]
Total past due loans	8,814	8,221
Current	1,141,874	1,066,475
Total loans	1,150,688	1,074,696
Non- accrual	9,710	8,688
Total Loans [Member] | Non ASC 310-30 [Member] | Owner-Occupied [Member]
Loans [Line Items]
Total past due loans	3,933	855
Current	232,402	220,689
Total loans	236,335	221,544
Non- accrual	2,786	2,056
Total Loans [Member] | Non ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total past due loans	94	28
Current	294,699	309,040
Total loans	294,793	309,068
Non- accrual	36	66
Total Loans [Member] | Non ASC 310-30 [Member] | Total Commercial Real Estate [Member]
Loans [Line Items]
Total past due loans	309	28
Current	450,842	437,614
Total loans	451,151	437,642
Non- accrual	36	66
Total Loans [Member] | Non ASC 310-30 [Member] | Senior lien
Loans [Line Items]
Total past due loans	2,959	2,991
Current	676,724	672,699
Total loans	679,683	675,690
Non- accrual	4,951	4,522
Total Loans [Member] | Non ASC 310-30 [Member] | Junior lien
Loans [Line Items]
Total past due loans	270	198
Current	51,032	52,473
Total loans	51,302	52,671
Loans 90 days past due and still accruing	99
Non- accrual	702	654
Total Loans [Member] | Non ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total past due loans	21,902	16,127
Current	1,582,759	1,505,023
Total loans	1,604,661	1,521,150
Non- accrual	27,852	25,294
Total Loans [Member] | Non ASC 310-30 [Member] | Agriculture [Member]
Loans [Line Items]
Total past due loans	2,534	501
Current	125,613	134,136
Total loans	128,147	134,637
Non- accrual	2,659	1,905
Total Loans [Member] | Non ASC 310-30 [Member] | Energy Loans [Member]
Loans [Line Items]
Total past due loans	6,621	6,550
Current	82,870	83,723
Total loans	89,491	90,273
Non- accrual	12,697	12,645
Total Loans [Member] | Non ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total past due loans	3,229	3,189
Current	727,756	725,172
Total loans	730,985	728,361
Loans 90 days past due and still accruing	99
Non- accrual	5,653	5,176
Total Loans [Member] | Non ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total past due loans	136	91
Current	26,658	27,825
Total loans	26,794	27,916
Loans 90 days past due and still accruing	6
Non- accrual	175	181
Total Loans [Member] | ASC 310-30 [Member]
Loans [Line Items]
Total loans	140,064	145,852
Total Loans [Member] | ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total loans	36,935	39,280
Total Loans [Member] | ASC 310-30 [Member] | Commercial Real Estate [Member]
Loans [Line Items]
Total loans	86,842	89,150
Total Loans [Member] | ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total loans	15,470	16,524
Total Loans [Member] | ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total loans	817	898
Total Loans [Member] | 30-59 Days Past Due | Non ASC 310-30 [Member]
Loans [Line Items]
Total past due loans	3,964	5,306
Total Loans [Member] | 30-59 Days Past Due | Non ASC 310-30 [Member] | Commercial and Industrial [Member]
Loans [Line Items]
Total past due loans	216	3,134
Total Loans [Member] | 30-59 Days Past Due | Non ASC 310-30 [Member] | Owner-Occupied [Member]
Loans [Line Items]
Total past due loans	1,441	583
Total Loans [Member] | 30-59 Days Past Due | Non ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total past due loans	68
Total Loans [Member] | 30-59 Days Past Due | Non ASC 310-30 [Member] | Total Commercial Real Estate [Member]
Loans [Line Items]
Total past due loans	68
Total Loans [Member] | 30-59 Days Past Due | Non ASC 310-30 [Member] | Senior lien
Loans [Line Items]
Total past due loans	1,543	888
Total Loans [Member] | 30-59 Days Past Due | Non ASC 310-30 [Member] | Junior lien
Loans [Line Items]
Total past due loans	86	115
Total Loans [Member] | 30-59 Days Past Due | Non ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total past due loans	2,148	4,220
Total Loans [Member] | 30-59 Days Past Due | Non ASC 310-30 [Member] | Agriculture [Member]
Loans [Line Items]
Total past due loans	491	501
Total Loans [Member] | 30-59 Days Past Due | Non ASC 310-30 [Member] | Energy Loans [Member]
Loans [Line Items]
Total past due loans		2
Total Loans [Member] | 30-59 Days Past Due | Non ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total past due loans	1,629	1,003
Total Loans [Member] | 30-59 Days Past Due | Non ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total past due loans	119	83
Total Loans [Member] | 60-89 Days Past Due | Non ASC 310-30 [Member]
Loans [Line Items]
Total past due loans	2,065	4,939
Total Loans [Member] | 60-89 Days Past Due | Non ASC 310-30 [Member] | Commercial Construction [Member]
Loans [Line Items]
Total past due loans	215
Total Loans [Member] | 60-89 Days Past Due | Non ASC 310-30 [Member] | Commercial and Industrial [Member]
Loans [Line Items]
Total past due loans	666	4,009
Total Loans [Member] | 60-89 Days Past Due | Non ASC 310-30 [Member] | Owner-Occupied [Member]
Loans [Line Items]
Total past due loans	720	216
Total Loans [Member] | 60-89 Days Past Due | Non ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total past due loans	26
Total Loans [Member] | 60-89 Days Past Due | Non ASC 310-30 [Member] | Total Commercial Real Estate [Member]
Loans [Line Items]
Total past due loans	241
Total Loans [Member] | 60-89 Days Past Due | Non ASC 310-30 [Member] | Senior lien
Loans [Line Items]
Total past due loans	410	645
Total Loans [Member] | 60-89 Days Past Due | Non ASC 310-30 [Member] | Junior lien
Loans [Line Items]
Total past due loans	17	61
Total Loans [Member] | 60-89 Days Past Due | Non ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total past due loans	1,386	4,225
Total Loans [Member] | 60-89 Days Past Due | Non ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total past due loans	427	706
Total Loans [Member] | 60-89 Days Past Due | Non ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total past due loans	11	8
Total Loans [Member] | Greater than 90 Days Past Due | Non ASC 310-30 [Member]
Loans [Line Items]
Total past due loans	19,547	9,190
Total Loans [Member] | Greater than 90 Days Past Due | Non ASC 310-30 [Member] | Commercial and Industrial [Member]
Loans [Line Items]
Total past due loans	7,932	1,078
Total Loans [Member] | Greater than 90 Days Past Due | Non ASC 310-30 [Member] | Owner-Occupied [Member]
Loans [Line Items]
Total past due loans	1,772	56
Total Loans [Member] | Greater than 90 Days Past Due | Non ASC 310-30 [Member] | Non Owner-Occupied [Member]
Loans [Line Items]
Total past due loans		28
Total Loans [Member] | Greater than 90 Days Past Due | Non ASC 310-30 [Member] | Total Commercial Real Estate [Member]
Loans [Line Items]
Total past due loans		28
Total Loans [Member] | Greater than 90 Days Past Due | Non ASC 310-30 [Member] | Senior lien
Loans [Line Items]
Total past due loans	1,006	1,458
Total Loans [Member] | Greater than 90 Days Past Due | Non ASC 310-30 [Member] | Junior lien
Loans [Line Items]
Total past due loans	167	22
Total Loans [Member] | Greater than 90 Days Past Due | Non ASC 310-30 [Member] | Commercial Loan [Member]
Loans [Line Items]
Total past due loans	18,368	7,682
Total Loans [Member] | Greater than 90 Days Past Due | Non ASC 310-30 [Member] | Agriculture [Member]
Loans [Line Items]
Total past due loans	2,043
Total Loans [Member] | Greater than 90 Days Past Due | Non ASC 310-30 [Member] | Energy Loans [Member]
Loans [Line Items]
Total past due loans	6,621	6,548
Total Loans [Member] | Greater than 90 Days Past Due | Non ASC 310-30 [Member] | Residential Real Estate Segment [Member]
Loans [Line Items]
Total past due loans	1,173	$ 1,480
Total Loans [Member] | Greater than 90 Days Past Due | Non ASC 310-30 [Member] | Consumer [Member]
Loans [Line Items]
Total past due loans	6
Non Accrual [Member]
Loans [Line Items]
Non- accrual	$ 33,700