Loans and Leases (Impaired loans not covered by loss share agreements) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with a related allowance, Unpaid Contractual Balance	$ 34,329	$ 34,329	$ 17,873
Impaired loans without a related allowance, Unpaid Contractual Balance	59,688	59,688	76,666
Total impaired loans held to maturity, Unpaid Contractual Balance	94,017	94,017	94,539
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with a related allowance, Loan Balance	34,052	34,052	17,787
Impaired loans without a related allowance, Loan Balance	49,650	49,650	65,789
Total impaired loans held to maturity, Loan Balance	83,702	83,702	83,576
Impaired loans, Related Allowance Recorded	5,229	5,229	4,624
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired loans with a related allowance, Avg. Loan Balance	23,904	20,253	24,650
Impaired loans without a related allowance, Avg. Loan Balance	55,200	56,400	64,846
Total impaired loans held to maturity, Avg. Loan Balance	79,104	76,653	89,496
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired loans with a related allowance, Interest Income Recognized	261	561	1,277
Impaired loans without a related allowance, Interest Income Recognized	176	300	1,497
Total impaired loans held to maturity, Interest Income Recognized	437	861	2,774
Commercial Portfolio Segment
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with a related allowance, Unpaid Contractual Balance	11,377	11,377	9,307
Impaired loans without a related allowance, Unpaid Contractual Balance	48,817	48,817	55,563
Total impaired loans held to maturity, Unpaid Contractual Balance	60,194	60,194	64,870
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with a related allowance, Loan Balance	11,156	11,156	9,288
Impaired loans without a related allowance, Loan Balance	39,509	39,509	45,326
Total impaired loans held to maturity, Loan Balance	50,665	50,665	54,614
Impaired loans, Related Allowance Recorded	1,482	1,482	2,462
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired loans with a related allowance, Avg. Loan Balance	10,788	9,544	17,753
Impaired loans without a related allowance, Avg. Loan Balance	35,540	38,101	45,627
Total impaired loans held to maturity, Avg. Loan Balance	46,328	47,645	63,380
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired loans with a related allowance, Interest Income Recognized	143	312	901
Impaired loans without a related allowance, Interest Income Recognized	77	125	875
Total impaired loans held to maturity, Interest Income Recognized	220	437	1,776
Agricultural Portfolio Segment
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with a related allowance, Unpaid Contractual Balance	16,019	16,019	1,493
Impaired loans without a related allowance, Unpaid Contractual Balance	4,149	4,149	14,654
Total impaired loans held to maturity, Unpaid Contractual Balance	20,168	20,168	16,147
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with a related allowance, Loan Balance	16,019	16,019	1,493
Impaired loans without a related allowance, Loan Balance	4,149	4,149	14,635
Total impaired loans held to maturity, Loan Balance	20,168	20,168	16,128
Impaired loans, Related Allowance Recorded	904	904	109
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired loans with a related allowance, Avg. Loan Balance	6,250	3,876	379
Impaired loans without a related allowance, Avg. Loan Balance	13,931	12,870	13,728
Total impaired loans held to maturity, Avg. Loan Balance	20,181	16,746	14,107
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired loans with a related allowance, Interest Income Recognized	80	168	83
Impaired loans without a related allowance, Interest Income Recognized	68	121	539
Total impaired loans held to maturity, Interest Income Recognized	148	289	622
Residential Portfolio Segment
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with a related allowance, Unpaid Contractual Balance	3,571	3,571	3,197
Impaired loans without a related allowance, Unpaid Contractual Balance	4,989	4,989	4,741
Total impaired loans held to maturity, Unpaid Contractual Balance	8,560	8,560	7,938
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with a related allowance, Loan Balance	3,515	3,515	3,170
Impaired loans without a related allowance, Loan Balance	4,435	4,435	4,273
Total impaired loans held to maturity, Loan Balance	7,950	7,950	7,443
Impaired loans, Related Allowance Recorded	915	915	783
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired loans with a related allowance, Avg. Loan Balance	3,488	3,404	2,737
Impaired loans without a related allowance, Avg. Loan Balance	4,118	3,923	3,861
Total impaired loans held to maturity, Avg. Loan Balance	7,606	7,327	6,598
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired loans with a related allowance, Interest Income Recognized	13	31	89
Impaired loans without a related allowance, Interest Income Recognized	22	39	65
Total impaired loans held to maturity, Interest Income Recognized	35	70	154
Consumer Portfolio Segment
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with a related allowance, Unpaid Contractual Balance	3,362	3,362	3,876
Impaired loans without a related allowance, Unpaid Contractual Balance	1,733	1,733	1,708
Total impaired loans held to maturity, Unpaid Contractual Balance	5,095	5,095	5,584
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with a related allowance, Loan Balance	3,362	3,362	3,836
Impaired loans without a related allowance, Loan Balance	1,557	1,557	1,555
Total impaired loans held to maturity, Loan Balance	4,919	4,919	5,391
Impaired loans, Related Allowance Recorded	1,928	1,928	1,270
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired loans with a related allowance, Avg. Loan Balance	3,378	3,429	3,781
Impaired loans without a related allowance, Avg. Loan Balance	1,611	1,506	1,630
Total impaired loans held to maturity, Avg. Loan Balance	4,989	4,935	5,411
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired loans with a related allowance, Interest Income Recognized	25	50	204
Impaired loans without a related allowance, Interest Income Recognized	9	15	18
Total impaired loans held to maturity, Interest Income Recognized	34	65	222
Commercial | Commercial Portfolio Segment
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with a related allowance, Unpaid Contractual Balance	1,427	1,427	2,904
Impaired loans without a related allowance, Unpaid Contractual Balance	20,082	20,082	6,596
Total impaired loans held to maturity, Unpaid Contractual Balance	21,509	21,509	9,500
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with a related allowance, Loan Balance	1,427	1,427	2,904
Impaired loans without a related allowance, Loan Balance	19,241	19,241	6,127
Total impaired loans held to maturity, Loan Balance	20,668	20,668	9,031
Impaired loans, Related Allowance Recorded	682	682	1,350
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired loans with a related allowance, Avg. Loan Balance	2,063	2,345	5,082
Impaired loans without a related allowance, Avg. Loan Balance	10,352	7,917	3,813
Total impaired loans held to maturity, Avg. Loan Balance	12,415	10,262	8,895
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired loans with a related allowance, Interest Income Recognized	11	30	88
Impaired loans without a related allowance, Interest Income Recognized	8	12	186
Total impaired loans held to maturity, Interest Income Recognized	19	42	274
Commercial Real Estate | Commercial Portfolio Segment
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with a related allowance, Unpaid Contractual Balance	9,950	9,950	6,403
Impaired loans without a related allowance, Unpaid Contractual Balance	28,735	28,735	48,967
Total impaired loans held to maturity, Unpaid Contractual Balance	38,685	38,685	55,370
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with a related allowance, Loan Balance	9,729	9,729	6,384
Impaired loans without a related allowance, Loan Balance	20,268	20,268	39,199
Total impaired loans held to maturity, Loan Balance	29,997	29,997	45,583
Impaired loans, Related Allowance Recorded	800	800	1,112
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired loans with a related allowance, Avg. Loan Balance	8,725	7,199	12,671
Impaired loans without a related allowance, Avg. Loan Balance	25,188	30,184	41,814
Total impaired loans held to maturity, Avg. Loan Balance	33,913	37,383	54,485
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired loans with a related allowance, Interest Income Recognized	132	282	813
Impaired loans without a related allowance, Interest Income Recognized	69	113	689
Total impaired loans held to maturity, Interest Income Recognized	$ 201	$ 395	$ 1,502