Loans, Allowance for Loan and Lease Losses, and Reserve for Off-Balance Sheet Credit Commitments (Details 7) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Past Due Loans and Leases
30-59 Days Past Due	$ 14,733	$ 13,467
60-89 Days Past Due	4,811	4,511
Greater Than 90 Days and Accruing	433	453
Nonaccrual	103,494	112,026
Total Past Due and Nonaccrual Loans	123,471	130,457
Current	13,601,180	12,178,928
Total Loans and Leases	13,724,651	12,309,385	12,164,209
Commercial
Past Due Loans and Leases
30-59 Days Past Due	4,993	6,817
60-89 Days Past Due	401	1,003
Greater Than 90 Days and Accruing	35
Nonaccrual	18,728	19,888
Total Past Due and Nonaccrual Loans	24,157	27,708
Current	5,530,364	4,818,886
Total Loans and Leases	5,554,521	4,846,594
Commercial real estate mortgages
Past Due Loans and Leases
30-59 Days Past Due	7,118	5,838
Nonaccrual	36,580	21,948
Total Past Due and Nonaccrual Loans	43,698	27,786
Current	2,419,966	2,082,963
Total Loans and Leases	2,463,664	2,110,749	2,059,114
Residential mortgage
Past Due Loans and Leases
30-59 Days Past Due		662
60-89 Days Past Due	3,325	3,508
Greater Than 90 Days and Accruing	379	379
Nonaccrual	11,680	9,771
Total Past Due and Nonaccrual Loans	15,384	14,320
Current	3,882,306	3,748,898
Total Loans and Leases	3,897,690	3,763,218	3,742,768
Fixed
Past Due Loans and Leases
30-59 Days Past Due		662
60-89 Days Past Due	3,325	525
Greater Than 90 Days and Accruing	379	379
Nonaccrual	6,530	5,572
Total Past Due and Nonaccrual Loans	10,234	7,138
Current	1,478,559	1,574,658
Total Loans and Leases	1,488,793	1,581,796
Variable
Past Due Loans and Leases
60-89 Days Past Due		2,983
Nonaccrual	5,150	4,199
Total Past Due and Nonaccrual Loans	5,150	7,182
Current	2,403,747	2,174,240
Total Loans and Leases	2,408,897	2,181,422
Real estate construction
Past Due Loans and Leases
30-59 Days Past Due	2,582
Nonaccrual	28,963	50,876
Total Past Due and Nonaccrual Loans	31,545	50,876
Current	210,592	264,733
Total Loans and Leases	242,137	315,609	335,712
Construction
Past Due Loans and Leases
Nonaccrual	15,080	15,582
Total Past Due and Nonaccrual Loans	15,080	15,582
Current	151,157	202,279
Total Loans and Leases	166,237	217,861
Land
Past Due Loans and Leases
30-59 Days Past Due	2,582
Nonaccrual	13,883	35,294
Total Past Due and Nonaccrual Loans	16,465	35,294
Current	59,435	62,454
Total Loans and Leases	75,900	97,748
Equity lines of credit
Past Due Loans and Leases
60-89 Days Past Due	950
Greater Than 90 Days and Accruing		74
Nonaccrual	6,946	8,669
Total Past Due and Nonaccrual Loans	7,896	8,743
Current	711,070	732,338
Total Loans and Leases	718,966	741,081	728,890
Installment loan
Past Due Loans and Leases
30-59 Days Past Due	40	150
60-89 Days Past Due	23
Nonaccrual	477	874
Total Past Due and Nonaccrual Loans	540	1,024
Current	137,092	131,623
Total Loans and Leases	137,632	132,647	130,923
Commercial Installment loan
Past Due Loans and Leases
Nonaccrual		4
Total Past Due and Nonaccrual Loans		4
Current	452	601
Total Loans and Leases	452	605
Consumer Installment loan
Past Due Loans and Leases
30-59 Days Past Due	40	150
60-89 Days Past Due	23
Nonaccrual	477	870
Total Past Due and Nonaccrual Loans	540	1,020
Current	136,640	131,022
Total Loans and Leases	137,180	132,042
Lease financing
Past Due Loans and Leases
60-89 Days Past Due	112
Greater Than 90 Days and Accruing	19
Nonaccrual	120
Total Past Due and Nonaccrual Loans	251
Current	709,790	399,487
Total Loans and Leases	$ 710,041	$ 399,487