Loans and Leases (Troubled debt restructurings on financing receivables) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013 loans	Mar. 31, 2012 loans
Financing Receivable, Modifications [Line Items]
Number of loans	7	1
Pre-modification recorded investment	$ 7,892	$ 19
Post-modification recorded investment	7,892	19
Commercial Portfolio Segment
Financing Receivable, Modifications [Line Items]
Number of loans	2	0
Pre-modification recorded investment	4,670	0
Post-modification recorded investment	4,670	0
Agricultural Portfolio Segment
Financing Receivable, Modifications [Line Items]
Number of loans	3	0
Pre-modification recorded investment	2,576	0
Post-modification recorded investment	2,576	0
Residential Portfolio Segment
Financing Receivable, Modifications [Line Items]
Number of loans	2	1
Pre-modification recorded investment	646	19
Post-modification recorded investment	646	19
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	2	0
Pre-modification recorded investment	4,670	0
Post-modification recorded investment	4,670	0
Commercial Real Estate | Commercial Portfolio Segment
Financing Receivable, Modifications [Line Items]
Number of loans	0	0
Pre-modification recorded investment	0	0
Post-modification recorded investment	$ 0	$ 0