Loans and Leases (Troubled Debt Restructurings on Financing Receivables) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 loans	Dec. 31, 2011 loans
Financing Receivable, Modifications [Line Items]
Number of Loans	5	32
Pre-Modification Recorded Investment	$ 1,508	$ 9,964
Post-Modification Recorded Investment	1,508	9,964
Commercial Portfolio Segment
Financing Receivable, Modifications [Line Items]
Number of Loans	1	16
Pre-Modification Recorded Investment	13	5,788
Post-Modification Recorded Investment	13	5,788
Agricultural Portfolio Segment
Financing Receivable, Modifications [Line Items]
Number of Loans	2	7
Pre-Modification Recorded Investment	256	2,994
Post-Modification Recorded Investment	256	2,994
Residential Portfolio Segment
Financing Receivable, Modifications [Line Items]
Number of Loans	2	9
Pre-Modification Recorded Investment	1,239	1,182
Post-Modification Recorded Investment	1,239	1,182
Consumer Portfolio Segment
Financing Receivable, Modifications [Line Items]
Number of Loans	0	0
Pre-Modification Recorded Investment	0	0
Post-Modification Recorded Investment	0	0
Commercial | Commercial Portfolio Segment
Financing Receivable, Modifications [Line Items]
Number of Loans	0	3
Pre-Modification Recorded Investment	0	124
Post-Modification Recorded Investment	0	124
Commercial Real Estate | Commercial Portfolio Segment
Financing Receivable, Modifications [Line Items]
Number of Loans	1	13
Pre-Modification Recorded Investment	13	5,664
Post-Modification Recorded Investment	$ 13	$ 5,664