Loans & Leases and Allowance for Credit Losses, Aging Analysis of Loan Portfolio by the Time Past Due (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	$ 827	$ 89	$ 35
60 to 89 Days Past Due	0	0	25
90 Days and Still Accruing	0	0	0
Nonaccrual	2,393	2,270	3,133
Total Past Due	3,220	2,359	3,193
Current	1,702,100	1,709,885	1,359,837
Total Loans & Leases	1,705,320	1,712,244	1,363,030
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	719	0	0
60 to 89 Days Past Due	0	0	0
90 Days and Still Accruing	0	0	0
Nonaccrual	103	0	0
Total Past Due	822	0	0
Current	528,728	491,903	402,865
Total Loans & Leases	529,550	491,903	402,865
Agricultural Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	0	0	0
60 to 89 Days Past Due	0	0	0
90 Days and Still Accruing	0	0	0
Nonaccrual	0	0	0
Total Past Due	0	0	0
Current	351,866	357,207	326,112
Total Loans & Leases	351,866	357,207	326,112
Real Estate Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	0	0	0
60 to 89 Days Past Due	0	0	0
90 Days and Still Accruing	0	0	0
Nonaccrual	0	0	0
Total Past Due	0	0	0
Current	101,616	96,519	55,751
Total Loans & Leases	101,616	96,519	55,751
Residential 1st Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	99	0	0
60 to 89 Days Past Due	0	0	0
90 Days and Still Accruing	0	0	0
Nonaccrual	74	77	316
Total Past Due	173	77	316
Current	182,258	171,803	155,778
Total Loans & Leases	182,431	171,880	156,094
Home Equity Lines & Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	0	79	30
60 to 89 Days Past Due	0	0	0
90 Days and Still Accruing	0	0	0
Nonaccrual	616	576	969
Total Past Due	616	655	999
Current	31,108	32,362	33,290
Total Loans & Leases	31,724	33,017	34,289
Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	0	0	0
60 to 89 Days Past Due	0	0	25
90 Days and Still Accruing	0	0	0
Nonaccrual	14	18	32
Total Past Due	14	18	57
Current	216,217	281,945	209,171
Total Loans & Leases	216,231	281,963	209,228
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	0	0	0
60 to 89 Days Past Due	0	0	0
90 Days and Still Accruing	0	0	0
Nonaccrual	1,573	1,586	1,801
Total Past Due	1,573	1,586	1,801
Current	234,568	229,233	154,001
Total Loans & Leases	236,141	230,819	155,802
Consumer & Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	9	10	5
60 to 89 Days Past Due	0	0	0
90 Days and Still Accruing	0	0	0
Nonaccrual	13	13	15
Total Past Due	22	23	20
Current	4,893	4,696	4,701
Total Loans & Leases	4,915	4,719	4,721
Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	0	0	0
60 to 89 Days Past Due	0	0	0
90 Days and Still Accruing	0	0	0
Nonaccrual	0	0	0
Total Past Due	0	0	0
Current	50,846	44,217	18,168
Total Loans & Leases	$ 50,846	$ 44,217	$ 18,168