Loans And Allowance For Loan Losses (Schedule Of Internal Ratings Of Loans) (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2010
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	$ 1,728,832	$ 1,690,346	$ 1,537,708
Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	1,645,840	1,587,576
Pass [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	416,801	414,436
Pass [Member] | Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	61,941	72,124
Pass [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	960,611	912,691
Pass [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	206,487	188,325
Special Mention [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	30,286	28,517
Special Mention [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	7,419	11,505
Special Mention [Member] | Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	348	1,094
Special Mention [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	22,236	15,721
Special Mention [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	283	197
Substandard [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	52,553	74,036
Substandard [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	11,176	16,346
Substandard [Member] | Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	2,353	9,144
Substandard [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	38,306	47,036
Substandard [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	718	1,510
Doubtful [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	153	217
Doubtful [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	54	90
Doubtful [Member] | Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	14	18
Doubtful [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	72	77
Doubtful [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	13	32
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	435,450	442,377
Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	64,656	82,380
Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	1,021,225	975,525
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	$ 207,501	$ 190,064