Loans and Allowance for Credit Losses Past Due Loan Status and Non-Accrual Loans by Portfolio Segment (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
31-59 Days Past Due	$ 59,634	$ 62,810
60-89 Days Past Due	31,223	43,583
>90 Days Past Due and Accruing	26,221	28,767
Non-accrual	184,832	257,761
Total >90 Days	211,053	286,528
Total Past Due	301,910	392,921
Current	11,842,694	11,576,049
Loans, net of unearned income	12,144,604	11,968,970
Commercial - industrial, financial, and agricultural
31-59 Days Past Due	8,474	9,955
60-89 Days Past Due	8,042	5,013
>90 Days Past Due and Accruing	1,259	5,240
Non-accrual	65,695	75,704
Total >90 Days	66,954	80,944
Total Past Due	83,470	95,912
Current	3,528,595	3,543,456
Loans, net of unearned income	3,612,065	3,639,368
Real-estate commercial mortage
31-59 Days Past Due	12,993	11,167
60-89 Days Past Due	8,473	14,437
>90 Days Past Due and Accruing	2,160	4,394
Non-accrual	54,960	109,412
Total >90 Days	57,120	113,806
Total Past Due	78,586	139,410
Current	4,585,840	4,463,186
Loans, net of unearned income	4,664,426	4,602,596
Commercial - Secured [Member]
31-59 Days Past Due	8,013	9,284
60-89 Days Past Due	8,030	4,498
>90 Days Past Due and Accruing	1,060	4,831
Non-accrual	63,602	73,048
Total >90 Days	64,662	77,879
Total Past Due	80,705	91,661
Current	3,332,739	3,301,899
Loans, net of unearned income	3,413,444	3,393,560
Commercial - Unsecured [Member]
31-59 Days Past Due	461	671
60-89 Days Past Due	12	515
>90 Days Past Due and Accruing	199	409
Non-accrual	2,093	2,656
Total >90 Days	2,292	3,065
Total Past Due	2,765	4,251
Current	195,856	241,557
Loans, net of unearned income	198,621	245,808
Real Estate - Home Equity [Member]
31-59 Days Past Due	9,579	7,439
60-89 Days Past Due	3,066	4,194
>90 Days Past Due and Accruing	5,579	5,714
Non-accrual	9,940	5,493
Total >90 Days	15,519	11,207
Total Past Due	28,164	22,840
Current	1,604,226	1,601,722
Loans, net of unearned income	1,632,390	1,624,562
Real-estate - residential mortgage
31-59 Days Past Due	21,827	23,877
60-89 Days Past Due	10,296	13,246
>90 Days Past Due and Accruing	13,333	8,502
Non-accrual	21,103	7,834
Total >90 Days	34,436	16,336
Total Past Due	66,559	53,459
Current	1,190,432	1,043,733
Loans, net of unearned income	1,256,991	1,097,192
Commercial Real Estate Construction Financing Receivable [Member]
31-59 Days Past Due	1,331	4,744
60-89 Days Past Due	0	4,824
>90 Days Past Due and Accruing	579	1,850
Non-accrual	31,426	58,894
Total >90 Days	32,005	60,744
Total Past Due	33,336	70,312
Current	550,782	545,133
Loans, net of unearned income	584,118	615,445
Construction - Commercial Residential [Member]
31-59 Days Past Due	466	2,372
60-89 Days Past Due	0	4,824
>90 Days Past Due and Accruing	251	1,656
Non-accrual	22,815	53,420
Total >90 Days	23,066	55,076
Total Past Due	23,532	62,272
Current	265,020	290,665
Loans, net of unearned income	288,552	352,937
Construction - Commercial [Member]
31-59 Days Past Due	0	31
60-89 Days Past Due	0	0
>90 Days Past Due and Accruing	0	128
Non-accrual	8,035	4,347
Total >90 Days	8,035	4,475
Total Past Due	8,035	4,506
Current	218,315	204,875
Loans, net of unearned income	226,350	209,381
Construction other [Member]
31-59 Days Past Due	865	2,341
60-89 Days Past Due	0	0
>90 Days Past Due and Accruing	328	66
Non-accrual	576	1,127
Total >90 Days	904	1,193
Total Past Due	1,769	3,534
Current	67,447	49,593
Loans, net of unearned income	69,216	53,127
Consumer
31-59 Days Past Due	4,768	4,703
60-89 Days Past Due	1,297	1,745
>90 Days Past Due and Accruing	3,302	3,016
Non-accrual	1,698	368
Total >90 Days	5,000	3,384
Total Past Due	11,065	9,832
Current	298,155	308,269
Loans, net of unearned income	309,220	318,101
Consumer - Direct [Member]
31-59 Days Past Due	2,842	2,706
60-89 Days Past Due	953	1,305
>90 Days Past Due and Accruing	3,157	2,833
Non-accrual	1,698	368
Total >90 Days	4,855	3,201
Total Past Due	8,650	7,212
Current	157,287	157,157
Loans, net of unearned income	165,937	164,369
Consumer - Indirect [Member]
31-59 Days Past Due	1,926	1,997
60-89 Days Past Due	344	440
>90 Days Past Due and Accruing	145	183
Non-accrual	0	0
Total >90 Days	145	183
Total Past Due	2,415	2,620
Current	140,868	151,112
Loans, net of unearned income	143,283	153,732
Finance Leases Portfolio Segment [Member]
31-59 Days Past Due	662	925
60-89 Days Past Due	49	124
>90 Days Past Due and Accruing	9	51
Non-accrual	10	56
Total >90 Days	19	107
Total Past Due	730	1,156
Current	84,664	70,550
Loans, net of unearned income	$ 85,394	$ 71,706