Loans and Leases (Impaired Loans Not Covered by Loss Share Agreements) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Loans with a Related Allowance, Unpaid Contractual Balance	$ 17,873	$ 26,531
Impaired Loans Without a Related Allowance, Unpaid Contractual Balance	76,666	102,591
Impaired Loans Held to Maturity, Unpaid Contractual Balance	94,539	129,122
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Loans With a Related Allowance, Loan Balance	17,787	26,494
Impaired Loans Without a Related Allowance, Loan Balance	65,789	73,947
Totals Impaired Loans Held to Maturity, Loan Balance	83,576	100,441
Impaired Loans, Related Allowance Recorded	4,624	5,480
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Loans With a Related Allowance, Year-to-Date Avg. Loan Balance	24,650	49,130
Impaired Loans Without a Related Allowance, Year-to-Date Avg. Loan Balance	64,846	76,943
Totals Impaired Loans Held to Maturity, Year-to-Date Avg. Loan Balance	89,496	126,073
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired Loans With a Related Allowance, Year-to-Date Interest Income Recognized	1,277	935
Impaired Loans Without a Related Allowance, Year-to-Date Interest Income Recognized	1,497	1,414
Totals Impaired Loans Held to Maturity, Year-to-Date Interest Income Recognized	2,774	2,349
Commercial Portfolio Segment
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Loans with a Related Allowance, Unpaid Contractual Balance	9,307	21,991
Impaired Loans Without a Related Allowance, Unpaid Contractual Balance	55,563	81,613
Impaired Loans Held to Maturity, Unpaid Contractual Balance	64,870	103,604
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Loans With a Related Allowance, Loan Balance	9,288	21,955
Impaired Loans Without a Related Allowance, Loan Balance	45,326	53,805
Totals Impaired Loans Held to Maturity, Loan Balance	54,614	75,760
Impaired Loans, Related Allowance Recorded	2,462	3,919
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Loans With a Related Allowance, Year-to-Date Avg. Loan Balance	17,753	41,866
Impaired Loans Without a Related Allowance, Year-to-Date Avg. Loan Balance	45,627	56,878
Totals Impaired Loans Held to Maturity, Year-to-Date Avg. Loan Balance	63,380	98,744
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired Loans With a Related Allowance, Year-to-Date Interest Income Recognized	901	846
Impaired Loans Without a Related Allowance, Year-to-Date Interest Income Recognized	875	806
Totals Impaired Loans Held to Maturity, Year-to-Date Interest Income Recognized	1,776	1,652
Agricultural Portfolio Segment
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Loans with a Related Allowance, Unpaid Contractual Balance	1,493	0
Impaired Loans Without a Related Allowance, Unpaid Contractual Balance	14,654	14,428
Impaired Loans Held to Maturity, Unpaid Contractual Balance	16,147	14,428
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Loans With a Related Allowance, Loan Balance	1,493	0
Impaired Loans Without a Related Allowance, Loan Balance	14,635	14,385
Totals Impaired Loans Held to Maturity, Loan Balance	16,128	14,385
Impaired Loans, Related Allowance Recorded	109	0
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Loans With a Related Allowance, Year-to-Date Avg. Loan Balance	379	2,722
Impaired Loans Without a Related Allowance, Year-to-Date Avg. Loan Balance	13,728	14,302
Totals Impaired Loans Held to Maturity, Year-to-Date Avg. Loan Balance	14,107	17,024
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired Loans With a Related Allowance, Year-to-Date Interest Income Recognized	83	0
Impaired Loans Without a Related Allowance, Year-to-Date Interest Income Recognized	539	557
Totals Impaired Loans Held to Maturity, Year-to-Date Interest Income Recognized	622	557
Residential Portfolio Segment
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Loans with a Related Allowance, Unpaid Contractual Balance	3,197	1,776
Impaired Loans Without a Related Allowance, Unpaid Contractual Balance	4,741	4,324
Impaired Loans Held to Maturity, Unpaid Contractual Balance	7,938	6,100
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Loans With a Related Allowance, Loan Balance	3,170	1,775
Impaired Loans Without a Related Allowance, Loan Balance	4,273	4,130
Totals Impaired Loans Held to Maturity, Loan Balance	7,443	5,905
Impaired Loans, Related Allowance Recorded	783	464
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Loans With a Related Allowance, Year-to-Date Avg. Loan Balance	2,737	1,854
Impaired Loans Without a Related Allowance, Year-to-Date Avg. Loan Balance	3,861	4,293
Totals Impaired Loans Held to Maturity, Year-to-Date Avg. Loan Balance	6,598	6,147
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired Loans With a Related Allowance, Year-to-Date Interest Income Recognized	89	57
Impaired Loans Without a Related Allowance, Year-to-Date Interest Income Recognized	65	46
Totals Impaired Loans Held to Maturity, Year-to-Date Interest Income Recognized	154	103
Consumer Portfolio Segment
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Loans with a Related Allowance, Unpaid Contractual Balance	3,876	2,764
Impaired Loans Without a Related Allowance, Unpaid Contractual Balance	1,708	2,226
Impaired Loans Held to Maturity, Unpaid Contractual Balance	5,584	4,990
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Loans With a Related Allowance, Loan Balance	3,836	2,764
Impaired Loans Without a Related Allowance, Loan Balance	1,555	1,627
Totals Impaired Loans Held to Maturity, Loan Balance	5,391	4,391
Impaired Loans, Related Allowance Recorded	1,270	1,097
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Loans With a Related Allowance, Year-to-Date Avg. Loan Balance	3,781	2,688
Impaired Loans Without a Related Allowance, Year-to-Date Avg. Loan Balance	1,630	1,470
Totals Impaired Loans Held to Maturity, Year-to-Date Avg. Loan Balance	5,411	4,158
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired Loans With a Related Allowance, Year-to-Date Interest Income Recognized	204	32
Impaired Loans Without a Related Allowance, Year-to-Date Interest Income Recognized	18	5
Totals Impaired Loans Held to Maturity, Year-to-Date Interest Income Recognized	222	37
Commercial | Commercial Portfolio Segment
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Loans with a Related Allowance, Unpaid Contractual Balance	2,904	8,433
Impaired Loans Without a Related Allowance, Unpaid Contractual Balance	6,596	1,737
Impaired Loans Held to Maturity, Unpaid Contractual Balance	9,500	10,170
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Loans With a Related Allowance, Loan Balance	2,904	8,397
Impaired Loans Without a Related Allowance, Loan Balance	6,127	896
Totals Impaired Loans Held to Maturity, Loan Balance	9,031	9,293
Impaired Loans, Related Allowance Recorded	1,350	1,990
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Loans With a Related Allowance, Year-to-Date Avg. Loan Balance	5,082	9,395
Impaired Loans Without a Related Allowance, Year-to-Date Avg. Loan Balance	3,813	2,221
Totals Impaired Loans Held to Maturity, Year-to-Date Avg. Loan Balance	8,895	11,616
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired Loans With a Related Allowance, Year-to-Date Interest Income Recognized	88	434
Impaired Loans Without a Related Allowance, Year-to-Date Interest Income Recognized	186	2
Totals Impaired Loans Held to Maturity, Year-to-Date Interest Income Recognized	274	436
Commercial Real Estate | Commercial Portfolio Segment
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Loans with a Related Allowance, Unpaid Contractual Balance	6,403	13,558
Impaired Loans Without a Related Allowance, Unpaid Contractual Balance	48,967	79,876
Impaired Loans Held to Maturity, Unpaid Contractual Balance	55,370	93,434
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Loans With a Related Allowance, Loan Balance	6,384	13,558
Impaired Loans Without a Related Allowance, Loan Balance	39,199	52,909
Totals Impaired Loans Held to Maturity, Loan Balance	45,583	66,467
Impaired Loans, Related Allowance Recorded	1,112	1,929
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Loans With a Related Allowance, Year-to-Date Avg. Loan Balance	12,671	32,471
Impaired Loans Without a Related Allowance, Year-to-Date Avg. Loan Balance	41,814	54,657
Totals Impaired Loans Held to Maturity, Year-to-Date Avg. Loan Balance	54,485	87,128
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired Loans With a Related Allowance, Year-to-Date Interest Income Recognized	813	412
Impaired Loans Without a Related Allowance, Year-to-Date Interest Income Recognized	689	804
Totals Impaired Loans Held to Maturity, Year-to-Date Interest Income Recognized	$ 1,502	$ 1,216