Loans And Allowance For Loan Losses (Schedule Of Past Due Loans) (Details) (USD $) In Thousands	Sep. 30, 2011		Dec. 31, 2010		Sep. 30, 2010
Financing Receivable, Recorded Investment, Past Due [Line Items]
15-59 Days Past Due	$ 13,523	[1]	$ 10,195	[1]
60-89 Days Past Due	710		1,990
Greater Than 90 Days	887		4,530
Total Past Due	15,120		16,715
Total Current	1,713,712		1,673,631
Total Loans	1,728,832		1,690,346		1,537,708
Total 90 Days Past Due Still Accruing	52		2,196		69
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
15-59 Days Past Due	1,640	[1]	2,138	[1]
60-89 Days Past Due	370		241
Greater Than 90 Days	88		713
Total Past Due	2,098		3,092
Total Current	433,352		439,285
Total Loans	435,450		442,377
Total 90 Days Past Due Still Accruing			20
Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
15-59 Days Past Due	244	[1]	371	[1]
60-89 Days Past Due	20
Total Past Due	264		371
Total Current	64,392		82,009
Total Loans	64,656		82,380
Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
15-59 Days Past Due	10,285	[1]	6,638	[1]
60-89 Days Past Due	223		1,569
Greater Than 90 Days	778		3,792
Total Past Due	11,286		11,999
Total Current	1,009,939		963,526
Total Loans	1,021,225		975,525
Total 90 Days Past Due Still Accruing	49		2,169
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
15-59 Days Past Due	1,354	[1]	1,048	[1]
60-89 Days Past Due	97		180
Greater Than 90 Days	21		25
Total Past Due	1,472		1,253
Total Current	206,029		188,811
Total Loans	207,501		190,064
Total 90 Days Past Due Still Accruing	$ 3		$ 7

[1] The Company monitors commercial, agricultural and real estate loans after such loans are 15 days past due. Consumer loans are monitored after such loans are 30 days past due.