Loans and Allowance for Credit Losses Allowance for Loan Losses by Portfolio Segment (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Loans and Leases Receivable, Allowance, Beginning Balance	$ 256,471,000	$ 274,271,000
Loans charged off	(140,366,000)	(161,333,000)	(151,425,000)
Loans Charged Off, Net Of Recoveries	(126,738,000)	(152,321,000)	(142,055,000)
Provision for loan losses	94,170,000	134,521,000
Loans and Leases Receivable, Allowance, Ending Balance	223,903,000	256,471,000	274,271,000
Change in provision allocated to commitments to lend to borrowers	170,000	479,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	144,728,000	159,894,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	79,175,000	96,577,000
Loans, net of unearned income	12,144,604,000	11,968,970,000
Real-estate commercial mortage
Loans and Leases Receivable, Allowance, Beginning Balance	85,112,000	40,831,000
Loans charged off	(51,988,000)	(26,032,000)
Loans Charged Off, Net Of Recoveries	(48,617,000)	(24,065,000)
Provision for loan losses	26,433,000	45,463,000
Impact of change in allowance methodology		22,883,000
Provision for loan losses, including impact of change in allowance methodology		68,346,000
Loans and Leases Receivable, Allowance, Ending Balance	62,928,000	85,112,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	41,316,000	49,052,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	21,612,000	36,060,000
Loans, net of unearned income	4,664,426,000	4,602,596,000
Commercial - industrial, financial, and agricultural
Loans and Leases Receivable, Allowance, Beginning Balance	74,896,000	101,436,000
Loans charged off	(41,868,000)	(52,301,000)
Loans Charged Off, Net Of Recoveries	(37,586,000)	(49,780,000)
Provision for loan losses	22,895,000	36,628,000
Impact of change in allowance methodology		(13,388,000)
Provision for loan losses, including impact of change in allowance methodology		23,240,000
Loans and Leases Receivable, Allowance, Ending Balance	60,205,000	74,896,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	41,421,000	46,471,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	18,784,000	28,425,000
Loans, net of unearned income	3,612,065,000	3,639,368,000
Real Estate - Home Equity [Member]
Loans and Leases Receivable, Allowance, Beginning Balance	12,841,000	6,454,000
Loans charged off	(10,147,000)	(6,397,000)
Loans Charged Off, Net Of Recoveries	(9,443,000)	(6,334,000)
Provision for loan losses	19,378,000	9,031,000
Impact of change in allowance methodology		3,690,000
Provision for loan losses, including impact of change in allowance methodology		12,721,000
Loans and Leases Receivable, Allowance, Ending Balance	22,776,000	12,841,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	14,396,000	9,765,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	8,380,000	3,076,000
Loans, net of unearned income	1,632,390,000	1,624,562,000
Real-estate - residential mortgage
Loans and Leases Receivable, Allowance, Beginning Balance	22,986,000	17,425,000
Loans charged off	(4,509,000)	(32,533,000)
Loans Charged Off, Net Of Recoveries	(4,050,000)	(32,208,000)
Provision for loan losses	15,600,000	29,873,000
Impact of change in allowance methodology		7,896,000
Provision for loan losses, including impact of change in allowance methodology		37,769,000
Loans and Leases Receivable, Allowance, Ending Balance	34,536,000	22,986,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	10,428,000	6,691,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	24,108,000	16,295,000
Loans, net of unearned income	1,256,991,000	1,097,192,000
Commercial Real Estate Construction Financing Receivable [Member]
Loans and Leases Receivable, Allowance, Beginning Balance	30,066,000	58,117,000
Loans charged off	(26,250,000)	(38,613,000)
Loans Charged Off, Net Of Recoveries	(23,436,000)	(36,867,000)
Provision for loan losses	10,657,000	33,587,000
Impact of change in allowance methodology		(24,771,000)
Provision for loan losses, including impact of change in allowance methodology		8,816,000
Loans and Leases Receivable, Allowance, Ending Balance	17,287,000	30,066,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	11,028,000	17,610,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	6,259,000	12,456,000
Loans, net of unearned income	584,118,000	615,445,000
Consumer
Loans and Leases Receivable, Allowance, Beginning Balance	2,083,000	4,669,000
Loans charged off	(3,323,000)	(3,289,000)
Loans Charged Off, Net Of Recoveries	(2,216,000)	(1,921,000)
Provision for loan losses	2,500,000	2,411,000
Impact of change in allowance methodology		(3,076,000)
Provision for loan losses, including impact of change in allowance methodology		(665,000)
Loans and Leases Receivable, Allowance, Ending Balance	2,367,000	2,083,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	2,342,000	1,855,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	25,000	228,000
Loans, net of unearned income	309,220,000	318,101,000
Leasing and Other and Overdrafts [Member]
Loans and Leases Receivable, Allowance, Beginning Balance	2,397,000	3,840,000
Loans charged off	(2,281,000)	(2,168,000)
Loans Charged Off, Net Of Recoveries	(1,390,000)	(1,146,000)
Provision for loan losses	1,745,000	647,000
Impact of change in allowance methodology		(944,000)
Provision for loan losses, including impact of change in allowance methodology		(297,000)
Loans and Leases Receivable, Allowance, Ending Balance	2,752,000	2,397,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	2,745,000	2,360,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	7,000	37,000
Loans, net of unearned income	85,394,000	71,706,000
Unallocated
Loans and Leases Receivable, Allowance, Beginning Balance	26,090,000	41,499,000
Loans charged off	0	0
Loans Charged Off, Net Of Recoveries	0	0
Provision for loan losses	(5,038,000)	(23,119,000)
Impact of change in allowance methodology		7,710,000
Provision for loan losses, including impact of change in allowance methodology		(15,409,000)
Loans and Leases Receivable, Allowance, Ending Balance	21,052,000	26,090,000
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	21,052,000	26,090,000
Subtotal [Member]
Impact of change in allowance methodology		0
Provision for loan losses, including impact of change in allowance methodology		$ 134,521,000