Loans and Allowance for Loan Losses (Loan Portfolio Credit Exposure) (Details) (USD $)	Sep. 30, 2012		Dec. 31, 2011		Sep. 30, 2011
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 19,748,918,000	[1],[2]	$ 20,091,799,000	[2],[3]	$ 20,112,130,000	[1]
Nonaccrual substandard loans	664,000,000		844,000,000
Deferred fees and costs, net	17,100,000		12,000,000		10,000,000
Home Equity Lines [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,572,986,000	[2]	1,619,585,000	[2]
Consumer Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,399,432,000	[2]	1,411,749,000	[2]
Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	257,922,000	[2]	273,098,000	[2]
Other Retail Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	738,319,000	[2]	575,475,000	[2]
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	9,052,692,000	[2]	8,941,274,000	[2]
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	6,727,567,000	[2]	7,270,618,000	[2]
Investment Properties [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,390,897,000	[2]	4,557,313,000	[2]
1-4 Family Properties [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,427,250,000	[2]	1,618,484,000	[2]
Land Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	909,420,000	[2]	1,094,821,000	[2]
Retail [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,968,659,000	[2]	3,879,907,000	[2]
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	16,590,146,000		15,943,399,000
Pass [Member] | Home Equity Lines [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,539,858,000		1,578,938,000
Pass [Member] | Consumer Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,345,706,000		1,344,648,000
Pass [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	256,005,000		270,624,000
Pass [Member] | Other Retail Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	721,488,000		562,623,000
Pass [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	7,827,462,000		7,265,761,000
Pass [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,899,627,000		4,920,805,000
Pass [Member] | Investment Properties [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,516,510,000		3,443,363,000
Pass [Member] | 1-4 Family Properties [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	930,368,000		977,083,000
Pass [Member] | Land Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	452,749,000		500,359,000
Pass [Member] | Retail [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,863,057,000		3,756,833,000
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,493,744,000		2,089,215,000
Special Mention [Member] | Home Equity Lines [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0		0
Special Mention [Member] | Consumer Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0		0
Special Mention [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0		0
Special Mention [Member] | Other Retail Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0		0
Special Mention [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	639,964,000		909,255,000
Special Mention [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	853,780,000		1,179,960,000
Special Mention [Member] | Investment Properties [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	524,909,000		778,009,000
Special Mention [Member] | 1-4 Family Properties [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	216,097,000		269,152,000
Special Mention [Member] | Land Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	112,774,000		132,799,000
Special Mention [Member] | Retail [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0		0
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,628,845,000		2,020,142,000
Substandard [Member] | Home Equity Lines [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	31,948,000	[4]	39,811,000	[4]
Substandard [Member] | Consumer Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	53,001,000	[4]	66,478,000	[4]
Substandard [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	605,000	[4]	948,000	[4]
Substandard [Member] | Other Retail Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	15,605,000	[4]	12,349,000	[4]
Substandard [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	571,960,000	[4]	754,934,000	[4]
Substandard [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	955,726,000		1,145,622,000
Substandard [Member] | Investment Properties [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	344,331,000	[4]	328,402,000	[4]
Substandard [Member] | 1-4 Family Properties [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	274,869,000	[4]	361,210,000	[4]
Substandard [Member] | Land Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	336,526,000	[4]	456,010,000	[4]
Substandard [Member] | Retail [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	101,159,000		119,586,000
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	31,572,000		35,555,000
Doubtful [Member] | Home Equity Lines [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	[5]	0	[5]
Doubtful [Member] | Consumer Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	[5]	0	[5]
Doubtful [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	[5]	0	[5]
Doubtful [Member] | Other Retail Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	[5]	0	[5]
Doubtful [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	13,306,000	[5]	11,324,000	[5]
Doubtful [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	18,266,000		24,231,000
Doubtful [Member] | Investment Properties [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,147,000	[5]	7,539,000	[5]
Doubtful [Member] | 1-4 Family Properties [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,748,000	[5]	11,039,000	[5]
Doubtful [Member] | Land Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	7,371,000	[5]	5,653,000	[5]
Doubtful [Member] | Retail [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0		0
Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,611,000		3,488,000
Loss [Member] | Home Equity Lines [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,180,000	[5],[6]	836,000	[5],[6]
Loss [Member] | Consumer Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	725,000	[5],[6]	623,000	[5],[6]
Loss [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,312,000	[5]	1,526,000	[5],[6]
Loss [Member] | Other Retail Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,226,000	[5],[6]	503,000	[5],[6]
Loss [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	[5]	0	[5]
Loss [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	168,000		0
Loss [Member] | Investment Properties [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	[5]	0	[5]
Loss [Member] | 1-4 Family Properties [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	168,000	[5]	0	[5]
Loss [Member] | Land Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	[5]	0	[5]
Loss [Member] | Retail [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 4,443,000		$ 3,488,000

[1] Total excludes $17.1 million in net deferred fees and costs

[2] Loan balances in each category expressed as a component of total loans, excluding deferred fees and costs.

[3] Total excludes $12.0 million in net deferred fees and costs

[4] Includes $664.0 million and $844.0 million of non-accrual substandard loans at September 30, 2012 and December 31, 2011, respectively.

[5] The loans within these risk grades are on non-accrual status.

[6] Represent amounts that were 120 days past due. These credits are downgraded to the loss category with an allowance for loan losses equal to the full loan amount and are charged off in the subsequent quarter.