Loans, Allowance for Loan and Lease Losses, and Reserve for Off-Balance Sheet Credit Commitments (Details 8) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
Past Due Loans and Leases
30-59 Days Past Due	$ 10,981	$ 29,273
60-89 Days Past Due	4,589	10,813
Greater Than 90 Days and Accruing	383	981
Nonaccrual	69,602	99,787
Total Past Due and Nonaccrual Loans	85,555	140,854
Current	16,480,578	14,677,441
Total Loans and Leases	16,566,133	14,818,295	13,724,651
Commercial
Past Due Loans and Leases
30-59 Days Past Due	8,052	6,207
60-89 Days Past Due	964	4,219
Greater Than 90 Days and Accruing	3	602
Nonaccrual	10,073	9,087
Total Past Due and Nonaccrual Loans	19,092	20,115
Current	7,107,066	6,191,238
Total Loans and Leases	7,126,158	6,211,353
Commercial real estate mortgages
Past Due Loans and Leases
30-59 Days Past Due	2,631	16,968
60-89 Days Past Due		3,249
Nonaccrual	19,020	33,198
Total Past Due and Nonaccrual Loans	21,651	53,415
Current	3,055,532	2,685,869
Total Loans and Leases	3,077,183	2,739,284	2,436,218
Residential mortgage
Past Due Loans and Leases
60-89 Days Past Due	3,613	1,969
Greater Than 90 Days and Accruing	379	379
Nonaccrual	9,674	9,603
Total Past Due and Nonaccrual Loans	13,666	11,951
Current	4,404,565	3,950,254
Total Loans and Leases	4,418,231	3,962,205	3,897,690
Fixed
Past Due Loans and Leases
60-89 Days Past Due	1,238	1,969
Greater Than 90 Days and Accruing	379	379
Nonaccrual	3,901	4,902
Total Past Due and Nonaccrual Loans	5,518	7,250
Current	1,457,866	1,458,224
Total Loans and Leases	1,463,384	1,465,474
Variable
Past Due Loans and Leases
60-89 Days Past Due	2,375
Nonaccrual	5,773	4,701
Total Past Due and Nonaccrual Loans	8,148	4,701
Current	2,946,699	2,492,030
Total Loans and Leases	2,954,847	2,496,731
Real estate construction
Past Due Loans and Leases
60-89 Days Past Due		859
Nonaccrual	25,471	40,882
Total Past Due and Nonaccrual Loans	25,471	41,741
Current	355,018	271,449
Total Loans and Leases	380,489	313,190	269,583
Construction
Past Due Loans and Leases
Nonaccrual	11,553	15,067
Total Past Due and Nonaccrual Loans	11,553	15,067
Current	339,138	239,740
Total Loans and Leases	350,691	254,807
Land
Past Due Loans and Leases
60-89 Days Past Due		859
Nonaccrual	13,918	25,815
Total Past Due and Nonaccrual Loans	13,918	26,674
Current	15,880	31,709
Total Loans and Leases	29,798	58,383
Home equity loans and lines of credit
Past Due Loans and Leases
30-59 Days Past Due	274	3,407
60-89 Days Past Due		480
Nonaccrual	5,289	6,424
Total Past Due and Nonaccrual Loans	5,563	10,311
Current	676,316	701,439
Total Loans and Leases	681,879	711,750	718,966
Installment loan
Past Due Loans and Leases
30-59 Days Past Due	24	58
60-89 Days Past Due		35
Nonaccrual	21	473
Total Past Due and Nonaccrual Loans	45	566
Current	152,062	142,227
Total Loans and Leases	152,107	142,793	137,632
Commercial Installment loan
Past Due Loans and Leases
Current	379	437
Total Loans and Leases	379	437
Consumer Installment loan
Past Due Loans and Leases
30-59 Days Past Due	24	58
60-89 Days Past Due		35
Nonaccrual	21	473
Total Past Due and Nonaccrual Loans	45	566
Current	151,683	141,790
Total Loans and Leases	151,728	142,356
Lease financing
Past Due Loans and Leases
30-59 Days Past Due		2,633
60-89 Days Past Due	12	2
Greater Than 90 Days and Accruing	1
Nonaccrual	54	120
Total Past Due and Nonaccrual Loans	67	2,755
Current	730,019	734,965
Total Loans and Leases	$ 730,086	$ 737,720