Loans and Allowances for Credit Losses Part 4 (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	$ 321,435	$ 382,472	$ 321,435	$ 382,472	$ 360,258
Impaired loans, recorded investment, total	278,937	306,723	278,937	306,723	294,365
Impaired loans, recorded investment with no related allowance	273,210	300,528	273,210	300,528	283,039
Impaired loans, recorded investment with related allowance	5,727	6,195	5,727	6,195	11,326
Impaired loans, related allowance	2,044	1,835	2,044	1,835	4,233
Impaired loans, average recorded investment	285,277	341,462	290,244	358,849
Impaired loans, interest income recognized	1,913	2,078	4,011	4,154
Commercial [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	35,747	57,285	35,747	57,285	43,230
Impaired loans, recorded investment, total	20,869	34,529	20,869	34,529	24,467
Impaired loans, recorded investment with no related allowance	19,612	33,082	19,612	33,082	23,140
Impaired loans, recorded investment with related allowance	1,257	1,447	1,257	1,447	1,327
Impaired loans, related allowance	552	278	552	278	230
Impaired loans, average recorded investment	20,366	48,141	22,670	51,672
Impaired loans, interest income recognized	0	0	0	0
Commercial [Member] | Energy [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	2,277	3,297	2,277	3,297	2,460
Impaired loans, recorded investment, total	2,277	3,087	2,277	3,087	2,460
Impaired loans, recorded investment with no related allowance	2,277	3,087	2,277	3,087	2,460
Impaired loans, recorded investment with related allowance	0	0	0	0	0
Impaired loans, related allowance	0	0	0	0	0
Impaired loans, average recorded investment	2,327	1,712	2,369	1,712
Impaired loans, interest income recognized	0	0	0	0
Commercial [Member] | Services [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	9,631	18,858	9,631	18,858	15,715
Impaired loans, recorded investment, total	7,448	10,123	7,448	10,123	12,090
Impaired loans, recorded investment with no related allowance	6,283	9,996	6,283	9,996	11,940
Impaired loans, recorded investment with related allowance	1,165	127	1,165	127	150
Impaired loans, related allowance	493	127	493	127	149
Impaired loans, average recorded investment	8,461	11,507	9,769	13,546
Impaired loans, interest income recognized	0	0	0	0
Commercial [Member] | Wholesale/retail [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	10,916	5,763	10,916	5,763	9,186
Impaired loans, recorded investment, total	6,700	4,175	6,700	4,175	3,077
Impaired loans, recorded investment with no related allowance	6,656	4,096	6,656	4,096	3,016
Impaired loans, recorded investment with related allowance	44	79	44	79	61
Impaired loans, related allowance	11	20	11	20	15
Impaired loans, average recorded investment	4,470	9,782	4,889	12,678
Impaired loans, interest income recognized	0	0	0	0
Commercial [Member] | Manufacturing [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	1,168	15,864	1,168	15,864	2,447
Impaired loans, recorded investment, total	876	12,230	876	12,230	2,007
Impaired loans, recorded investment with no related allowance	876	12,230	876	12,230	2,007
Impaired loans, recorded investment with related allowance	0	0	0	0	0
Impaired loans, related allowance	0	0	0	0	0
Impaired loans, average recorded investment	1,362	17,816	1,442	17,641
Impaired loans, interest income recognized	0	0	0	0
Commercial [Member] | Healthcare [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	3,357	4,400	3,357	4,400	4,256
Impaired loans, recorded investment, total	2,670	3,310	2,670	3,310	3,166
Impaired loans, recorded investment with no related allowance	2,622	2,069	2,622	2,069	2,050
Impaired loans, recorded investment with related allowance	48	1,241	48	1,241	1,116
Impaired loans, related allowance	48	131	48	131	66
Impaired loans, average recorded investment	2,816	5,628	2,918	4,398
Impaired loans, interest income recognized	0	0	0	0
Commercial [Member] | Integrated food services [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	0	0	0	0	684
Impaired loans, recorded investment, total	0	0	0	0	684
Impaired loans, recorded investment with no related allowance	0	0	0	0	684
Impaired loans, recorded investment with related allowance	0	0	0	0	0
Impaired loans, related allowance	0	0	0	0	0
Impaired loans, average recorded investment	0	0	342	0
Impaired loans, interest income recognized	0	0	0	0
Commercial [Member] | Other commercial and industrial [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	8,398	9,103	8,398	9,103	8,482
Impaired loans, recorded investment, total	898	1,604	898	1,604	983
Impaired loans, recorded investment with no related allowance	898	1,604	898	1,604	983
Impaired loans, recorded investment with related allowance	0	0	0	0	0
Impaired loans, related allowance	0	0	0	0	0
Impaired loans, average recorded investment	930	1,696	941	1,697
Impaired loans, interest income recognized	0	0	0	0
Commercial Real Estate [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	67,467	119,669	67,467	119,669	86,001
Impaired loans, recorded investment, total	58,693	80,214	58,693	80,214	60,626
Impaired loans, recorded investment with no related allowance	54,595	76,125	54,595	76,125	53,051
Impaired loans, recorded investment with related allowance	4,098	4,089	4,098	4,089	7,575
Impaired loans, related allowance	1,194	1,280	1,194	1,280	3,109
Impaired loans, average recorded investment	61,936	83,346	59,661	89,704
Impaired loans, interest income recognized	0	0	0	0
Commercial Real Estate [Member] | Construction and land development [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	24,752	78,447	24,752	78,447	44,721
Impaired loans, recorded investment, total	21,135	46,050	21,135	46,050	26,131
Impaired loans, recorded investment with no related allowance	20,841	45,477	20,841	45,477	25,575
Impaired loans, recorded investment with related allowance	294	573	294	573	556
Impaired loans, related allowance	102	155	102	155	155
Impaired loans, average recorded investment	22,299	49,233	23,633	53,962
Impaired loans, interest income recognized	0	0	0	0
Commercial Real Estate [Member] | Retail [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	9,827	9,395	9,827	9,395	9,797
Impaired loans, recorded investment, total	8,406	7,908	8,406	7,908	8,117
Impaired loans, recorded investment with no related allowance	8,406	5,541	8,406	5,541	8,117
Impaired loans, recorded investment with related allowance	0	2,367	0	2,367	0
Impaired loans, related allowance	0	905	0	905	0
Impaired loans, average recorded investment	8,664	7,051	8,262	7,386
Impaired loans, interest income recognized	0	0	0	0
Commercial Real Estate [Member] | Office [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	9,245	13,744	9,245	13,744	8,949
Impaired loans, recorded investment, total	7,828	10,589	7,828	10,589	6,829
Impaired loans, recorded investment with no related allowance	7,820	10,364	7,820	10,364	6,604
Impaired loans, recorded investment with related allowance	8	225	8	225	225
Impaired loans, related allowance	8	21	8	21	21
Impaired loans, average recorded investment	10,340	10,661	7,329	11,023
Impaired loans, interest income recognized	0	0	0	0
Commercial Real Estate [Member] | Multifamily [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	6,447	3,333	6,447	3,333	3,189
Impaired loans, recorded investment, total	6,447	3,219	6,447	3,219	2,706
Impaired loans, recorded investment with no related allowance	4,415	3,219	4,415	3,219	2,706
Impaired loans, recorded investment with related allowance	2,032	0	2,032	0	0
Impaired loans, related allowance	196	0	196	0	0
Impaired loans, average recorded investment	5,474	3,317	4,577	3,366
Impaired loans, interest income recognized	0	0	0	0
Commercial Real Estate [Member] | Industrial [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	0	0	0	0	3,968
Impaired loans, recorded investment, total	0	0	0	0	3,968
Impaired loans, recorded investment with no related allowance	0	0	0	0	0
Impaired loans, recorded investment with related allowance	0	0	0	0	3,968
Impaired loans, related allowance	0	0	0	0	2,290
Impaired loans, average recorded investment	1,099	0	1,984	0
Impaired loans, interest income recognized	0	0	0	0
Commercial Real Estate [Member] | Other commercial real estate [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	17,196	14,750	17,196	14,750	15,377
Impaired loans, recorded investment, total	14,877	12,448	14,877	12,448	12,875
Impaired loans, recorded investment with no related allowance	13,113	11,524	13,113	11,524	10,049
Impaired loans, recorded investment with related allowance	1,764	924	1,764	924	2,826
Impaired loans, related allowance	888	199	888	199	643
Impaired loans, average recorded investment	14,060	13,084	13,876	13,967
Impaired loans, interest income recognized	0	0	0	0
Residential Mortgage [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	216,118	197,919	216,118	197,919	228,149
Impaired loans, recorded investment, total	197,338	184,967	197,338	184,967	206,563
Impaired loans, recorded investment with no related allowance	197,086	184,350	197,086	184,350	204,264
Impaired loans, recorded investment with related allowance	252	617	252	617	2,299
Impaired loans, related allowance	178	235	178	235	769
Impaired loans, average recorded investment	200,870	202,632	205,540	212,208
Impaired loans, interest income recognized	1,913	2,078	4,011	4,154
Residential Mortgage [Member] | Permanent mortgage [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	42,983	26,504	42,983	26,504	51,153
Impaired loans, recorded investment, total	32,747	18,136	32,747	18,136	39,863
Impaired loans, recorded investment with no related allowance	32,495	17,519	32,495	17,519	37,564
Impaired loans, recorded investment with related allowance	252	617	252	617	2,299
Impaired loans, related allowance	178	235	178	235	769
Impaired loans, average recorded investment	35,450	20,479	36,304	21,751
Impaired loans, interest income recognized	285	398	603	795
Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	165,431	166,824	165,431	166,824	170,740
Impaired loans, recorded investment, total	156,887	162,240	156,887	162,240	160,444
Impaired loans, recorded investment with no related allowance	156,887	162,240	156,887	162,240	160,444
Impaired loans, recorded investment with related allowance	0	0	0	0	0
Impaired loans, related allowance	0	0	0	0	0
Impaired loans, average recorded investment	158,038	177,537	162,256	185,961
Impaired loans, interest income recognized	1,628	1,680	3,408	3,359
Residential Mortgage [Member] | Home equity [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	7,704	4,591	7,704	4,591	6,256
Impaired loans, recorded investment, total	7,704	4,591	7,704	4,591	6,256
Impaired loans, recorded investment with no related allowance	7,704	4,591	7,704	4,591	6,256
Impaired loans, recorded investment with related allowance	0	0	0	0	0
Impaired loans, related allowance	0	0	0	0	0
Impaired loans, average recorded investment	7,382	4,616	6,980	4,496
Impaired loans, interest income recognized	0	0	0	0
Consumer [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	2,103	7,599	2,103	7,599	2,878
Impaired loans, recorded investment, total	2,037	7,013	2,037	7,013	2,709
Impaired loans, recorded investment with no related allowance	1,917	6,971	1,917	6,971	2,584
Impaired loans, recorded investment with related allowance	120	42	120	42	125
Impaired loans, related allowance	120	42	120	42	125
Impaired loans, average recorded investment	2,105	7,343	2,373	5,265
Impaired loans, interest income recognized	0	0	0	0
Consumer [Member] | Indirect automobile [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	1,188	2,257	1,188	2,257	1,578
Impaired loans, recorded investment, total	1,188	2,257	1,188	2,257	1,578
Impaired loans, recorded investment with no related allowance	1,188	2,257	1,188	2,257	1,578
Impaired loans, recorded investment with related allowance	0	0	0	0	0
Impaired loans, related allowance	0	0	0	0	0
Impaired loans, average recorded investment	1,254	2,433	1,383	2,226
Impaired loans, interest income recognized	0	0	0	0
Consumer [Member] | Other consumer [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	915	5,342	915	5,342	1,300
Impaired loans, recorded investment, total	849	4,756	849	4,756	1,131
Impaired loans, recorded investment with no related allowance	729	4,714	729	4,714	1,006
Impaired loans, recorded investment with related allowance	120	42	120	42	125
Impaired loans, related allowance	120	42	120	42	125
Impaired loans, average recorded investment	851	4,910	990	3,039
Impaired loans, interest income recognized	$ 0	$ 0	$ 0	$ 0