Loans and Allowance for Credit Losses Allowance for Loan Losses by Portfolio Segment (Details) (USD $)	3 Months Ended			9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010	Sep. 30, 2011		Sep. 30, 2010
Loans and Leases Receivable, Allowance, Beginning Balance	$ 266,683,000			$ 274,271,000
Loans charged off	(32,897,000)		(38,797,000)	(119,101,000)		(100,321,000)
Recoveries of loans previously charged off	2,081,000		3,294,000	7,420,000		7,642,000
Loans Charged Off, Net Of Recoveries	(30,816,000)		(35,503,000)	(111,681,000)		(92,679,000)
Provision for loan losses	31,111,000	[1]		104,388,000
Impact of change in allowance methodology				0
Provision for loan losses, including impact of change in allowance methodology				104,388,000	[1]
Loans and Leases Receivable, Allowance, Ending Balance	266,978,000			266,978,000
Change in provision allocated to commitments to lend to borrowers	(111,000)			612,000
Provision for Loan and Lease Losses	31,000,000		40,000,000	105,000,000		120,000,000
Real-estate commercial mortage
Loans and Leases Receivable, Allowance, Beginning Balance	73,598,000			40,831,000
Loans charged off	(5,730,000)			(22,851,000)
Recoveries of loans previously charged off	249,000			1,975,000
Loans Charged Off, Net Of Recoveries	(5,481,000)			(20,876,000)
Provision for loan losses	13,066,000	[1]		38,345,000
Impact of change in allowance methodology				22,883,000
Provision for loan losses, including impact of change in allowance methodology				61,228,000	[1]
Loans and Leases Receivable, Allowance, Ending Balance	81,183,000			81,183,000
Commercial - industrial, financial, and agricultural
Loans and Leases Receivable, Allowance, Beginning Balance	82,613,000			101,436,000
Loans charged off	(14,840,000)			(43,582,000)
Recoveries of loans previously charged off	695,000			2,089,000
Loans Charged Off, Net Of Recoveries	(14,145,000)			(41,493,000)
Provision for loan losses	11,669,000	[1]		33,582,000
Impact of change in allowance methodology				(13,388,000)
Provision for loan losses, including impact of change in allowance methodology				20,194,000	[1]
Loans and Leases Receivable, Allowance, Ending Balance	80,137,000			80,137,000
Real-estate - home equity
Loans and Leases Receivable, Allowance, Beginning Balance	9,560,000			6,454,000
Loans charged off	(1,158,000)			(4,276,000)
Recoveries of loans previously charged off	23,000			26,000
Loans Charged Off, Net Of Recoveries	(1,135,000)			(4,250,000)
Provision for loan losses	1,418,000	[1]		3,949,000
Impact of change in allowance methodology				3,690,000
Provision for loan losses, including impact of change in allowance methodology				7,639,000	[1]
Loans and Leases Receivable, Allowance, Ending Balance	9,843,000			9,843,000
Real-estate - residential mortgage
Loans and Leases Receivable, Allowance, Beginning Balance	31,912,000			17,425,000
Loans charged off	(1,514,000)			(14,217,000)
Recoveries of loans previously charged off	36,000			270,000
Loans Charged Off, Net Of Recoveries	(1,478,000)			(13,947,000)
Provision for loan losses	2,902,000	[1]		21,962,000
Impact of change in allowance methodology				7,896,000
Provision for loan losses, including impact of change in allowance methodology				29,858,000	[1]
Loans and Leases Receivable, Allowance, Ending Balance	33,336,000			33,336,000
Real-estate - construction
Loans and Leases Receivable, Allowance, Beginning Balance	30,570,000			58,117,000
Loans charged off	(8,535,000)			(29,897,000)
Recoveries of loans previously charged off	595,000			1,237,000
Loans Charged Off, Net Of Recoveries	(7,940,000)			(28,660,000)
Provision for loan losses	10,415,000	[1]		28,359,000
Impact of change in allowance methodology				(24,771,000)
Provision for loan losses, including impact of change in allowance methodology				3,588,000	[1]
Loans and Leases Receivable, Allowance, Ending Balance	33,045,000			33,045,000
Consumer
Loans and Leases Receivable, Allowance, Beginning Balance	1,755,000			4,669,000
Loans charged off	(634,000)			(2,606,000)
Recoveries of loans previously charged off	291,000			1,033,000
Loans Charged Off, Net Of Recoveries	(343,000)			(1,573,000)
Provision for loan losses	2,990,000	[1]		4,382,000
Impact of change in allowance methodology				(3,076,000)
Provision for loan losses, including impact of change in allowance methodology				1,306,000	[1]
Loans and Leases Receivable, Allowance, Ending Balance	4,402,000			4,402,000
Leasing and Other and Overdrafts [Member]
Loans and Leases Receivable, Allowance, Beginning Balance	1,787,000			3,840,000
Loans charged off	(486,000)			(1,672,000)
Recoveries of loans previously charged off	192,000			790,000
Loans Charged Off, Net Of Recoveries	(294,000)			(882,000)
Provision for loan losses	768,000	[1]		247,000
Impact of change in allowance methodology				(944,000)
Provision for loan losses, including impact of change in allowance methodology				(697,000)	[1]
Loans and Leases Receivable, Allowance, Ending Balance	2,261,000			2,261,000
Unallocated
Loans and Leases Receivable, Allowance, Beginning Balance	34,888,000			41,499,000	[2]
Loans charged off	0			0
Recoveries of loans previously charged off	0			0
Loans Charged Off, Net Of Recoveries	0			0
Provision for loan losses	(12,117,000)	[1]		(26,438,000)
Impact of change in allowance methodology				7,710,000
Provision for loan losses, including impact of change in allowance methodology				(18,728,000)	[1]
Loans and Leases Receivable, Allowance, Ending Balance	$ 22,771,000	[2]		$ 22,771,000	[2]

[1] Provision for loan losses is net of a $111,000 decrease and $612,000 increase in provision applied to unfunded commitments for the three and nine months ended September 30, 2011, respectively. The total provision for credit losses, comprised of allocations for both funded and unfunded loans, was $31.0 million and $105.0 million for the three and nine months ended September 30, 2011, respectively.

[2] The Corporation’s unallocated allowance, which was approximately 9% and 15% as of September 30, 2011 and December 31, 2010, respectively, was reasonable and appropriate as the estimates used in the allocation process are inherently imprecise.