Loans And Allowance For Loan Losses (Schedule Of Internal Ratings Of Loans) (Details) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010
Total loans	$ 1,719,415	$ 1,690,346	$ 1,519,672
Pass [Member]
Total loans	1,627,679	1,587,576
Pass [Member] | Commercial [Member]
Total loans	417,357	414,436
Pass [Member] | Agricultural [Member]
Total loans	57,080	72,124
Pass [Member] | Real Estate [Member]
Total loans	952,275	912,691
Pass [Member] | Consumer [Member]
Total loans	200,967	188,325
Special Mention [Member]
Total loans	27,567	28,517
Special Mention [Member] | Commercial [Member]
Total loans	9,185	11,505
Special Mention [Member] | Agricultural [Member]
Total loans	961	1,094
Special Mention [Member] | Real Estate [Member]
Total loans	17,088	15,721
Special Mention [Member] | Consumer [Member]
Total loans	333	197
Substandard [Member]
Total loans	63,965	74,036
Substandard [Member] | Commercial [Member]
Total loans	12,834	16,346
Substandard [Member] | Agricultural [Member]
Total loans	3,026	9,144
Substandard [Member] | Real Estate [Member]
Total loans	47,358	47,036
Substandard [Member] | Consumer [Member]
Total loans	747	1,510
Doubtful [Member]
Total loans	204	217
Doubtful [Member] | Commercial [Member]
Total loans	101	90
Doubtful [Member] | Agricultural [Member]
Total loans	16	18
Doubtful [Member] | Real Estate [Member]
Total loans	74	77
Doubtful [Member] | Consumer [Member]
Total loans	13	32
Commercial [Member]
Total loans	439,477	442,377
Agricultural [Member]
Total loans	61,083	82,380
Real Estate [Member]
Total loans	1,016,795	975,525
Consumer [Member]
Total loans	$ 202,060	$ 190,064