Loans and Allowance for Credit Losses Summary Of Gross Loans (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	$ 11,902,097	$ 11,940,505
Unearned income	(6,442)	(7,198)
Loans, net of unearned income	11,895,655	11,933,307
Real-estate commercial mortage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	4,491,155	4,375,980
Loans, net of unearned income	4,491,155	4,375,980
Commercial - industrial, financial, and agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	3,690,164	3,704,384
Loans, net of unearned income	3,690,164	3,704,384
Real-estate - home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	1,630,880	1,641,777
Loans, net of unearned income	1,630,880	1,641,777
Real-estate - residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	1,041,463	995,990
Loans, net of unearned income	1,041,463	995,990
Real-estate - construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	648,398	801,185
Loans, net of unearned income	648,398	801,185
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	327,054	350,161
Loans, net of unearned income	327,054	350,161
Finance Leases Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	59,337	61,017
Bank Overdrafts [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	$ 13,646	$ 10,011