Loans, Allowance for Loan and Lease Losses, and Reserve for Off-Balance Sheet Credit Commitments (Details 5) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011
Past Due Loans and Leases
30-59 Days Past Due	$ 30,489	$ 13,467
60-89 Days Past Due	23,235	4,511
Greater Than 90 Days and Accruing	2,065	453
Nonaccrual	98,656	112,026
Total Past Due and Nonaccrual Loans	154,445	130,457
Current	13,352,764	12,178,928
Total Loans and Leases	13,507,209	12,309,385	11,663,123
Commercial
Past Due Loans and Leases
30-59 Days Past Due	6,864	6,817
60-89 Days Past Due	2,218	1,003
Nonaccrual	18,936	19,888
Total Past Due and Nonaccrual Loans	28,018	27,708
Current	5,351,471	4,818,886
Total Loans and Leases	5,379,489	4,846,594
Commercial real estate mortgages
Past Due Loans and Leases
30-59 Days Past Due	21,290	5,838
60-89 Days Past Due	20,859
Nonaccrual	28,780	21,948
Total Past Due and Nonaccrual Loans	70,929	27,786
Current	2,353,404	2,082,963
Total Loans and Leases	2,424,333	2,110,749	1,930,269
Residential mortgage
Past Due Loans and Leases
30-59 Days Past Due		662
60-89 Days Past Due		3,508
Greater Than 90 Days and Accruing	1,244	379
Nonaccrual	14,064	9,771
Total Past Due and Nonaccrual Loans	15,308	14,320
Current	3,807,322	3,748,898
Total Loans and Leases	3,822,630	3,763,218	3,710,765
Fixed
Past Due Loans and Leases
30-59 Days Past Due		662
60-89 Days Past Due		525
Greater Than 90 Days and Accruing	1,244	379
Nonaccrual	5,000	5,572
Total Past Due and Nonaccrual Loans	6,244	7,138
Current	1,493,281	1,574,658
Total Loans and Leases	1,499,525	1,581,796
Variable
Past Due Loans and Leases
60-89 Days Past Due		2,983
Nonaccrual	9,064	4,199
Total Past Due and Nonaccrual Loans	9,064	7,182
Current	2,314,041	2,174,240
Total Loans and Leases	2,323,105	2,181,422
Real estate construction
Past Due Loans and Leases
30-59 Days Past Due	1,717
Nonaccrual	29,676	50,876
Total Past Due and Nonaccrual Loans	31,393	50,876
Current	270,436	264,733
Total Loans and Leases	301,829	315,609	355,014
Construction
Past Due Loans and Leases
30-59 Days Past Due	1,717
Nonaccrual	15,126	15,582
Total Past Due and Nonaccrual Loans	16,843	15,582
Current	219,930	202,279
Total Loans and Leases	236,773	217,861
Land
Past Due Loans and Leases
Nonaccrual	14,550	35,294
Total Past Due and Nonaccrual Loans	14,550	35,294
Current	50,506	62,454
Total Loans and Leases	65,056	97,748
Equity lines of credit
Past Due Loans and Leases
30-59 Days Past Due	520
Greater Than 90 Days and Accruing	322	74
Nonaccrual	6,505	8,669
Total Past Due and Nonaccrual Loans	7,347	8,743
Current	733,923	732,338
Total Loans and Leases	741,270	741,081	735,899
Installment loan
Past Due Loans and Leases
30-59 Days Past Due	37	150
Nonaccrual	575	874
Total Past Due and Nonaccrual Loans	612	1,024
Current	129,588	131,623
Total Loans and Leases	130,200	132,647	130,924
Commercial Installment loan
Past Due Loans and Leases
Nonaccrual		4
Total Past Due and Nonaccrual Loans		4
Current	467	601
Total Loans and Leases	467	605
Consumer Installment loan
Past Due Loans and Leases
30-59 Days Past Due	37	150
Nonaccrual	575	870
Total Past Due and Nonaccrual Loans	612	1,020
Current	129,121	131,022
Total Loans and Leases	129,733	132,042
Lease financing
Past Due Loans and Leases
30-59 Days Past Due	61
60-89 Days Past Due	158
Greater Than 90 Days and Accruing	499
Nonaccrual	120
Total Past Due and Nonaccrual Loans	838
Current	706,620	399,487
Total Loans and Leases	$ 707,458	$ 399,487