Loans and Allowances for Credit Losses Part 5 (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	$ 101,613	$ 89,628	$ 97,985
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	40,832	45,735	48,126
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	60,781	43,893	49,859
Troubled Debt Restructuring, Specific allowance	515	436	273
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	997	5,271
Accruing [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	47,942	36,763	38,515
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	13,184	20,276	8,755
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	34,758	16,487	29,760
Troubled Debt Restructuring, Specific allowance	0	0	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	48
Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	53,671	52,865	59,470
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	27,648	25,459	39,371
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	26,023	27,406	20,099
Troubled Debt Restructuring, Specific allowance	515	436	273
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	997	5,223
Commercial [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	4,778	5,914	5,521
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	2,373	2,554	3,525
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	2,405	3,360	1,996
Troubled Debt Restructuring, Specific allowance	305	22	60
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	0
Commercial [Member] | Energy [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	0	0	0
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	0	0	0
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	0	0
Troubled Debt Restructuring, Specific allowance	0	0	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	0
Commercial [Member] | Services [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	2,441	3,199	2,492
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	1,195	992	2,099
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	1,246	2,207	393
Troubled Debt Restructuring, Specific allowance	292	0	45
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	0
Commercial [Member] | Wholesale/retail [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	1,481	1,676	2,290
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	1,015	1,480	1,362
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	466	196	928
Troubled Debt Restructuring, Specific allowance	13	22	15
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	0
Commercial [Member] | Manufacturing [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	0	0	0
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	0	0	0
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	0	0
Troubled Debt Restructuring, Specific allowance	0	0	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	0
Commercial [Member] | Healthcare [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	0	82	64
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	0	82	64
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	0	0
Troubled Debt Restructuring, Specific allowance	0	0	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	0
Commercial [Member] | Integrated food services [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	0	0	0
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	0	0	0
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	0	0
Troubled Debt Restructuring, Specific allowance	0	0	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	0
Commercial [Member] | Other commercial and industrial [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	856	957	675
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	163	0	0
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	693	957	675
Troubled Debt Restructuring, Specific allowance	0	0	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	0
Commercial Real Estate [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	26,764	36,371	30,599
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	10,002	14,785	21,043
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	16,762	21,586	9,556
Troubled Debt Restructuring, Specific allowance	76	335	76
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	627	5,166
Commercial Real Estate [Member] | Construction and land development [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	12,770	21,834	14,898
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	2,479	10,413	9,989
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	10,291	11,421	4,909
Troubled Debt Restructuring, Specific allowance	76	76	76
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	2,692
Commercial Real Estate [Member] | Retail [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	6,139	3,635	6,785
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	2,359	1,200	5,735
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	3,780	2,435	1,050
Troubled Debt Restructuring, Specific allowance	0	0	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	627	0
Commercial Real Estate [Member] | Office [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	2,966	3,419	3,899
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	1,883	1,133	1,920
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	1,083	2,286	1,979
Troubled Debt Restructuring, Specific allowance	0	0	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	269
Commercial Real Estate [Member] | Multifamily [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	0	0	0
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	0	0	0
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	0	0
Troubled Debt Restructuring, Specific allowance	0	0	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	0
Commercial Real Estate [Member] | Industrial [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	0	0	0
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	0	0	0
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	0	0
Troubled Debt Restructuring, Specific allowance	0	0	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	0
Commercial Real Estate [Member] | Other commercial real estate [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	4,889	7,483	5,017
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	3,281	2,039	3,399
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	1,608	5,444	1,618
Troubled Debt Restructuring, Specific allowance	0	259	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	2,205
Residential Mortgage [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	47,942	36,763	38,515
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	13,184	20,276	8,755
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	34,758	16,487	29,760
Troubled Debt Restructuring, Specific allowance	0	0	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	48
Residential Mortgage [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	21,206	7,027	20,490
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	14,514	4,575	12,214
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	6,692	2,452	8,276
Troubled Debt Restructuring, Specific allowance	54	79	54
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	370	57
Residential Mortgage [Member] | Permanent mortgage [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	0	3,993	0
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	0	2,706	0
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	0	1,287	0
Troubled Debt Restructuring, Specific allowance	0	0	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	48
Residential Mortgage [Member] | Permanent mortgage [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	19,230	7,027	20,490
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	12,670	4,575	12,214
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	6,560	2,452	8,276
Troubled Debt Restructuring, Specific allowance	54	79	54
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	370	57
Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	47,942	32,770	38,515
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	13,184	17,570	8,755
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	34,758	15,200	29,760
Troubled Debt Restructuring, Specific allowance	0	0	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	0
Residential Mortgage [Member] | Home equity [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	1,976	0	0
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	1,844	0	0
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	132	0	0
Troubled Debt Restructuring, Specific allowance	0	0	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	0
Consumer [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	923	3,553	2,860
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	759	3,545	2,589
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	164	8	271
Troubled Debt Restructuring, Specific allowance	80	0	83
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	0
Consumer [Member] | Indirect automobile [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	390	0	532
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	372	0	492
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	18	0	40
Troubled Debt Restructuring, Specific allowance	0	0	0
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	0	0
Consumer [Member] | Other consumer [Member] | Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructuring, Recorded Investment	533	3,553	2,328
Troubled Debt Restructuring, Performing in Accordance With Modified Terms	387	3,545	2,097
Troubled Debt Restructuring, Not Performing in Accordance With Modified Terms	146	8	231
Troubled Debt Restructuring, Specific allowance	80	0	83
Financing Receivables, Impaired, Troubled Debt Restructuring, Charge-offs	$ 0	$ 0