Loans & Leases and Allowance for Credit Losses, Aging Analysis of Loan Portfolio by the Time Past Due (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days and Still Accruing	$ 0	$ 0	$ 0
Nonaccrual	2,904	2,270	2,497
Total Past Due	3,330	2,359	2,601
Current	1,906,940	1,709,885	1,613,170
Total Loans & Leases	1,910,270	1,712,244	1,615,771
30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	230	89	104
60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	196	0	0
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days and Still Accruing	0	0	0
Nonaccrual	696	0	0
Total Past Due	696	0	0
Current	558,047	491,903	473,505
Total Loans & Leases	558,743	491,903	473,505
Commercial Real Estate [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0	0
Commercial Real Estate [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0	0
Agricultural Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days and Still Accruing	0	0	0
Nonaccrual	0	0	0
Total Past Due	0	0	0
Current	432,610	357,207	364,161
Total Loans & Leases	432,610	357,207	364,161
Agricultural Real Estate [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0	0
Agricultural Real Estate [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0	0
Real Estate Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days and Still Accruing	0	0	0
Nonaccrual	0	0	0
Total Past Due	0	0	0
Current	161,762	96,519	104,463
Total Loans & Leases	161,762	96,519	104,463
Real Estate Construction [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0	0
Real Estate Construction [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0	0
Residential 1st Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days and Still Accruing	0	0	0
Nonaccrual	68	77	283
Total Past Due	338	77	283
Current	196,555	171,803	168,027
Total Loans & Leases	196,893	171,880	168,310
Residential 1st Mortgages [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	74	0	0
Residential 1st Mortgages [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	196	0	0
Home Equity Lines & Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days and Still Accruing	0	0	0
Nonaccrual	576	576	575
Total Past Due	726	655	667
Current	31,107	32,362	32,616
Total Loans & Leases	31,833	33,017	33,283
Home Equity Lines & Loans [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	150	79	92
Home Equity Lines & Loans [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0	0
Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days and Still Accruing	0	0	0
Nonaccrual	8	18	25
Total Past Due	8	18	25
Current	249,775	281,945	237,496
Total Loans & Leases	249,783	281,963	237,521
Agricultural [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0	0
Agricultural [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0	0
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days and Still Accruing	0	0	0
Nonaccrual	1,545	1,586	1,600
Total Past Due	1,545	1,586	1,600
Current	208,946	229,233	191,204
Total Loans & Leases	210,491	230,819	192,804
Commercial [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0	0
Commercial [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0	0
Consumer & Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days and Still Accruing	0	0	0
Nonaccrual	11	13	14
Total Past Due	17	23	26
Current	6,718	4,696	4,790
Total Loans & Leases	6,735	4,719	4,816
Consumer & Other [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6	10	12
Consumer & Other [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0	0
Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
90 Days and Still Accruing	0	0	0
Nonaccrual	0	0	0
Total Past Due	0	0	0
Current	61,420	44,217	36,908
Total Loans & Leases	61,420	44,217	36,908
Leases [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0	0
Leases [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 0	$ 0	$ 0