Loans (Narrative) (Details)		3 Months Ended			9 Months Ended
		Sep. 30, 2015 USD ($) number		Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) number		Sep. 30, 2014 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)	Jun. 30, 2014 USD ($)	Dec. 31, 2013 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructurings loans		$ 304,700,000		$ 346,000,000	$ 304,700,000		$ 346,000,000
Allowance for loan losses		210,814,000		238,641,000	210,814,000		238,641,000	$ 221,351,000	$ 232,448,000	$ 243,628,000	$ 253,809,000
Average balance of impaired loans		337,301,000		367,299,000	343,935,000		377,673,000
Interest income recognized on impaired loan		$ 1,718,000		1,668,000	5,086,000		5,015,000
Forbearance agreements time period		6 months
Loans, net of unearned income		$ 16,725,492,000	[1]	15,812,017,000	16,725,492,000	[1]	15,812,017,000		16,230,166,000
Provision/(provision credit) for loan losses		1,000,000		6,000,000	8,000,000		21,000,000
Loan loss provision on PCI loans		100,000		400,000	400,000		2,100,000
Allowance - purchased credit impaired loans		2,919,000		2,839,000	2,919,000		2,839,000
Permanent Mortgage Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		$ 20,076,000		20,221,000	$ 20,076,000		20,221,000	22,377,000	19,122,000	23,727,000	22,491,000
TDR, reduction of interest rate by increment, basis points		0.25%			0.25%
TDRS Maturities		40 years
Loans, net of unearned income		$ 463,893,000		572,789,000	$ 463,893,000		572,789,000		538,961,000
Modified interest rate increase		1.00%			1.00%
Provision/(provision credit) for loan losses		$ (1,492,000)		(3,145,000)	$ 2,467,000		(84,000)
Allowance - purchased credit impaired loans		0		0	0		0
Loans Held-For-Sale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructurings loans		$ 72,600,000		83,100,000	72,600,000		83,100,000
Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage		32.00%
Consumer Real Estate Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage		29.00%
Allowance for loan losses		$ 82,472,000		118,395,000	82,472,000		118,395,000	85,457,000	113,011,000	118,037,000	126,785,000
TDRS Maturities		30 years
Loans, net of unearned income	[2]	$ 4,813,936,000		5,130,988,000	4,813,936,000		5,130,988,000		5,048,071,000
Provision/(provision credit) for loan losses		(776,000)		8,154,000	(25,465,000)		9,300,000
Allowance - purchased credit impaired loans		504,000		58,000	504,000		58,000
Modified Loans Classified As A TDR
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		$ 51,200,000		$ 60,900,000	$ 51,200,000		$ 60,900,000
Ratio of the allowance for loan losses to loans		17.00%		18.00%	17.00%		18.00%
Loans To Mortgage Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage contributed in total loan		8.00%			8.00%
Concentration risk, percentage					14.00%
Commercial loans		$ 1,375,320,000		$ 957,641,000	$ 1,375,320,000		$ 957,641,000
Loans, net of unearned income		1,375,320,000		957,641,000	1,375,320,000		957,641,000
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		96,811,000		85,320,000	96,811,000		85,320,000
Average balance of impaired loans		59,714,000		72,053,000	62,614,000		82,311,000
Interest income recognized on impaired loan		276,000		200,000	841,000		645,000
Commercial loans		$ 11,098,339,000		9,755,723,000	11,098,339,000		9,755,723,000
Time period of default probability		1 year
Allowance - purchased credit impaired loans		$ 2,414,000		2,781,000	2,414,000		2,781,000
Credit Card & Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		11,455,000		14,705,000	11,455,000		14,705,000	$ 13,275,000	14,730,000	$ 17,452,000	$ 7,484,000
Loans, net of unearned income		349,324,000		352,517,000	349,324,000		352,517,000		358,131,000
Provision/(provision credit) for loan losses		666,000		84,000	7,256,000		16,014,000
Allowance - purchased credit impaired loans		$ 1,000		0	$ 1,000		0
Credit Card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Credit card workout program, granted rate reduction		0.00%			0.00%
Loans, net of unearned income		$ 190,990,000		188,372,000	$ 190,990,000		188,372,000
Heloc And Real Estate Installment Classes
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDR, reduction of interest rate by increment, basis points		0.25%			0.25%
Restricted And Secured Consumer Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income		$ 59,300,000		81,100,000	$ 59,300,000		81,100,000		$ 76,800,000
Finance And Insurance Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage contributed in total loan		13.00%			13.00%
Concentration risk, percentage					22.00%
Commercial loans		$ 2,100,000,000			$ 2,100,000,000
Finance Insurance And Loans To Mortgage Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage contributed in total loan		36.00%			36.00%
Maximum | Permanent Mortgage Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Modified interest rate time period		5 years
Maximum | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forbearance agreements time period		12 months
Maximum | Credit Card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payment reductions, time period		1 year
Credit card workout program, term extension		5 years
Maximum | Heloc And Real Estate Installment Classes
Accounts, Notes, Loans and Financing Receivable [Line Items]
Modified interest rate time period		5 years
Minimum | Permanent Mortgage Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Modified interest rate		2.00%			2.00%
Modified interest rate time period		5 years
Minimum | Credit Card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payment reductions, time period		6 months
Minimum | Heloc And Real Estate Installment Classes
Accounts, Notes, Loans and Financing Receivable [Line Items]
Modified interest rate		1.00%			1.00%
Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | number		13			13
Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | number		14			14
Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | number		15			15
Unlikely to be Collected Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | number		16			16
PD Grade 1
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		$ 127,000		0	$ 127,000		0
Lowest expected default probability | number		1			1
PD Grade 12
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		$ 2,975,000		1,383,000	$ 2,975,000		1,383,000
PD Grade 13
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		4,256,000		$ 6,716,000	4,256,000		$ 6,716,000
PD Grade 13 | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans		$ 500,000			$ 500,000
LGD Grade 1
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | number		1			1
LGD Grade 12
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | number		12			12
Loan Reassessed | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans		$ 1,000,000			$ 1,000,000

[1] September 30, 2015 includes $30.7 million of held-to-maturity consumer mortgage loans secured by residential real estate in process of foreclosure.

[2] (a) Balances as of September 30, 2015 and 2014, and December 31, 2014 include $ 59. 3 million, $ 81 . 1 million, and $ 76.8 million of restricted real estate loans, respectively. See Note 13 - Variable Interest Entities for additional information.