Allowance for Credit Losses, Allocation of The Allowance For Loan Losses by Portfolio Segment and By Impairment Methodology (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Allowance for Credit Losses [Roll Forward]
Beginning Balance	$ 34,274	$ 34,217
Charge-Offs	(276)	(891)
Recoveries	228	523
Provision	1,175	425
Ending Balance	35,401	34,274
Ending Balance Individually Evaluated for Impairment	2,197	1,616
Ending Balance Collectively Evaluated for Impairment	33,204	32,658
Loans & Leases [Abstract]
Ending Balance	1,712,244	1,388,236
Ending Balance Individually Evaluated for Impairment	33,584	35,616
Ending Balance Collectively Evaluated for Impairment	1,678,660	1,352,620
Commercial Real Estate [Member]
Allowance for Credit Losses [Roll Forward]
Beginning Balance	5,178	6,464
Charge-Offs	0	(6)
Recoveries	11	0
Provision	2,653	(1,280)
Ending Balance	7,842	5,178
Ending Balance Individually Evaluated for Impairment	377	0
Ending Balance Collectively Evaluated for Impairment	7,465	5,178
Loans & Leases [Abstract]
Ending Balance	491,903	407,514
Ending Balance Individually Evaluated for Impairment	20,066	22,176
Ending Balance Collectively Evaluated for Impairment	471,837	385,338
Agricultural Real Estate [Member]
Allowance for Credit Losses [Roll Forward]
Beginning Balance	3,576	2,877
Charge-Offs	0	(575)
Recoveries	0	0
Provision	609	1,274
Ending Balance	4,185	3,576
Ending Balance Individually Evaluated for Impairment	0	0
Ending Balance Collectively Evaluated for Impairment	4,185	3,576
Loans & Leases [Abstract]
Ending Balance	357,207	328,264
Ending Balance Individually Evaluated for Impairment	0	0
Ending Balance Collectively Evaluated for Impairment	357,207	328,264
Real Estate Construction [Member]
Allowance for Credit Losses [Roll Forward]
Beginning Balance	654	986
Charge-Offs	0	0
Recoveries	0	0
Provision	1,015	(332)
Ending Balance	1,669	654
Ending Balance Individually Evaluated for Impairment	0	0
Ending Balance Collectively Evaluated for Impairment	1,669	654
Loans & Leases [Abstract]
Ending Balance	96,519	41,092
Ending Balance Individually Evaluated for Impairment	4,386	4,500
Ending Balance Collectively Evaluated for Impairment	92,133	36,592
Residential 1st Mortgages [Member]
Allowance for Credit Losses [Roll Forward]
Beginning Balance	1,108	1,219
Charge-Offs	(73)	(16)
Recoveries	0	0
Provision	(13)	(95)
Ending Balance	1,022	1,108
Ending Balance Individually Evaluated for Impairment	422	414
Ending Balance Collectively Evaluated for Impairment	600	694
Loans & Leases [Abstract]
Ending Balance	171,880	151,292
Ending Balance Individually Evaluated for Impairment	2,108	2,072
Ending Balance Collectively Evaluated for Impairment	169,772	149,220
Home Equity Lines and Loans [Member]
Allowance for Credit Losses [Roll Forward]
Beginning Balance	2,767	3,235
Charge-Offs	(70)	(91)
Recoveries	58	115
Provision	(329)	(492)
Ending Balance	2,426	2,767
Ending Balance Individually Evaluated for Impairment	329	209
Ending Balance Collectively Evaluated for Impairment	2,097	2,558
Loans & Leases [Abstract]
Ending Balance	33,017	35,477
Ending Balance Individually Evaluated for Impairment	1,643	1,045
Ending Balance Collectively Evaluated for Impairment	31,374	34,432
Agricultural [Member]
Allowance for Credit Losses [Roll Forward]
Beginning Balance	12,205	10,437
Charge-Offs	0	(23)
Recoveries	8	42
Provision	(6,109)	1,749
Ending Balance	6,104	12,205
Ending Balance Individually Evaluated for Impairment	114	122
Ending Balance Collectively Evaluated for Impairment	5,990	12,083
Loans & Leases [Abstract]
Ending Balance	281,963	256,414
Ending Balance Individually Evaluated for Impairment	461	522
Ending Balance Collectively Evaluated for Impairment	281,502	255,892
Commercial [Member]
Allowance for Credit Losses [Roll Forward]
Beginning Balance	5,697	7,963
Charge-Offs	(1)	(60)
Recoveries	86	312
Provision	2,413	(2,518)
Ending Balance	8,195	5,697
Ending Balance Individually Evaluated for Impairment	914	820
Ending Balance Collectively Evaluated for Impairment	7,281	4,877
Loans & Leases [Abstract]
Ending Balance	230,819	150,398
Ending Balance Individually Evaluated for Impairment	4,874	5,250
Ending Balance Collectively Evaluated for Impairment	225,945	145,148
Consumer & Other [Member]
Allowance for Credit Losses [Roll Forward]
Beginning Balance	176	182
Charge-Offs	(132)	(120)
Recoveries	65	54
Provision	109	60
Ending Balance	218	176
Ending Balance Individually Evaluated for Impairment	41	51
Ending Balance Collectively Evaluated for Impairment	177	125
Loans & Leases [Abstract]
Ending Balance	4,719	5,052
Ending Balance Individually Evaluated for Impairment	46	51
Ending Balance Collectively Evaluated for Impairment	4,673	5,001
Leases [Member]
Allowance for Credit Losses [Roll Forward]
Beginning Balance	639	0
Charge-Offs	0	0
Recoveries	0	0
Provision	1,572	639
Ending Balance	2,211	639
Ending Balance Individually Evaluated for Impairment	0	0
Ending Balance Collectively Evaluated for Impairment	2,211	639
Loans & Leases [Abstract]
Ending Balance	44,217	12,733
Ending Balance Individually Evaluated for Impairment	0	0
Ending Balance Collectively Evaluated for Impairment	44,217	12,733
Unallocated [Member]
Allowance for Credit Losses [Roll Forward]
Beginning Balance	2,274	854
Charge-Offs	0	0
Recoveries	0	0
Provision	(745)	1,420
Ending Balance	1,529	2,274
Ending Balance Individually Evaluated for Impairment	0	0
Ending Balance Collectively Evaluated for Impairment	1,529	2,274
Loans & Leases [Abstract]
Ending Balance	0	0
Ending Balance Individually Evaluated for Impairment	0	0
Ending Balance Collectively Evaluated for Impairment	0	0
Restructured Loans [Member]
Loans & Leases [Abstract]
Ending Balance Individually Evaluated for Impairment	$ 26,400	$ 28,400

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A valuation allowance for financing receivables that are expected to be uncollectible.

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-Name Accounting Standards Codification

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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Amount of recovery of financing receivables doubtful of collection that were previously charged off.

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Amount of direct write-downs of financing receivables charged against the allowance.

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The balance of financing receivables that were collectively evaluated for impairment.

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The balance of financing receivables that were individually evaluated for impairment.

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

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