Loans and Allowance for Credit Losses Allowance for Loan Losses by Portfolio Segment (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Beginning Balance	$ 256,471		$ 274,271
Loans charged off	(30,259)		(45,529)
Recoveries of loans previously charged off	2,219		3,187
Net loans charged off	(28,040)		(42,342)
Provision for loan losses	28,065	[1]	38,343	[1]
Ending Balance	256,496		270,272
Real-estate commercial mortage [Member]
Beginning Balance	85,112		40,831
Loans charged off	(11,891)		(10,047)
Recoveries of loans previously charged off	816		1,535
Net loans charged off	(11,075)		(8,512)
Provision for loan losses	7,615	[1]	16,239	[1]
Ending Balance	81,652		48,558
Commercial - industrial, financial, and agricultural
Beginning Balance	74,896		101,436
Loans charged off	(5,669)		(13,336)
Recoveries of loans previously charged off	636		391
Net loans charged off	(5,033)		(12,945)
Provision for loan losses	9,893	[1]	11,689	[1]
Ending Balance	79,756		100,180
Real-estate - home equity [Member]
Beginning Balance	12,841		6,454
Loans charged off	(2,206)		(1,468)
Recoveries of loans previously charged off	20		1
Net loans charged off	(2,186)		(1,467)
Provision for loan losses	2,428	[1]	669	[1]
Ending Balance	13,083		5,656
Real-estate - residential mortgage [Member]
Beginning Balance	22,986		17,425
Loans charged off	(847)		(4,996)
Recoveries of loans previously charged off	73		44
Net loans charged off	(774)		(4,952)
Provision for loan losses	2,639	[1]	7,102	[1]
Ending Balance	24,851		19,575
Real-estate - construction
Beginning Balance	30,066		58,117
Loans charged off	(8,571)		(13,894)
Recoveries of loans previously charged off	64		563
Net loans charged off	(8,507)		(13,331)
Provision for loan losses	9,627	[1]	10,705	[1]
Ending Balance	31,186		55,491
Consumer
Beginning Balance	2,083		4,669
Loans charged off	(634)		(1,291)
Recoveries of loans previously charged off	350		309
Net loans charged off	(284)		(982)
Provision for loan losses	(156)	[1]	1,049	[1]
Ending Balance	1,643		4,736
Leasing and other and overdrafts [Member]
Beginning Balance	2,397		3,840
Loans charged off	(441)		(497)
Recoveries of loans previously charged off	260		344
Net loans charged off	(181)		(153)
Provision for loan losses	1,058	[1]	(1,111)	[1]
Ending Balance	3,274		2,576
Unallocated
Beginning Balance	26,090		41,499
Loans charged off	0		0
Recoveries of loans previously charged off	0		0
Net loans charged off	0		0
Provision for loan losses	(5,039)	[1]	(7,999)	[1]
Ending Balance	$ 21,051	[2]	$ 33,500	[2]

[1] Provision for loan losses is gross of a $65,000 and $343,000 decrease, respectively, in provision applied to unfunded commitments for the three months ended March 31, 2012 and 2011. The total provision for credit losses, comprised of allocations for both funded and unfunded loans, was $28.0 million and $38.0 million for the three months ended March 31, 2012 and 2011, respectively

[2] The Corporation’s unallocated allowance, which was approximately 8% and 12% as of March 31, 2012 and 2011, respectively, was reasonable and appropriate as the estimates used in the allocation process are inherently imprecise.