Loans (Narrative) (Details)		3 Months Ended			6 Months Ended
		Jun. 30, 2015 USD ($) number		Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) number		Jun. 30, 2014 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructurings loans		$ 310,600,000		$ 350,900,000	$ 310,600,000		$ 350,900,000
Allowance for loan losses		221,351,000		243,628,000	221,351,000		243,628,000	$ 228,328,000	$ 232,448,000	$ 247,246,000	$ 253,809,000
Average balance of impaired loans		348,644,000		374,714,000	347,253,000		382,859,000
Interest income recognized on impaired loan		$ 1,709,000		1,666,000	3,369,000		3,347,000
Forbearance agreements time period		6 months
Loans, net of unearned income		$ 16,936,772,000	[1]	15,795,709,000	16,936,772,000	[1]	15,795,709,000		16,230,166,000
Provision/(provision credit) for loan losses		2,000,000		5,000,000	7,000,000		15,000,000
Loan loss provision on PCI loans		300,000		600,000	600,000		1,700,000
Allowance - purchased credit impaired loans		2,784,000		2,455,000	2,784,000		2,455,000
Permanent Mortgage Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		$ 22,377,000		23,727,000	$ 22,377,000		23,727,000	20,186,000	19,122,000	22,521,000	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		$ 487,679,000		594,001,000	$ 487,679,000		594,001,000		538,961,000
Modified interest rate increase		1.00%			1.00%
Provision/(provision credit) for loan losses		$ 2,329,000		1,391,000	$ 3,959,000		3,061,000
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		$ 80,800,000		139,500,000	80,800,000		139,500,000
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		$ 85,457,000		118,037,000	85,457,000		118,037,000	109,245,000	113,011,000	123,409,000	126,785,000
TDRS Maturities		30 years
Loans, net of unearned income	[2]	$ 4,870,271,000		5,218,930,000	4,870,271,000		5,218,930,000		5,048,071,000
Provision/(provision credit) for loan losses		(24,736,000)		(2,768,000)	(24,689,000)		1,146,000
Allowance - purchased credit impaired loans		493,000		41,000	493,000		41,000
Modified Loans Classified As A TDR
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		$ 61,000,000		$ 65,800,000	$ 61,000,000		$ 65,800,000
Ratio of the allowance for loan losses to loans		20.00%		19.00%	20.00%		19.00%
Loans To Mortgage Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage contributed in total loan		11.00%			11.00%
Concentration risk, percentage					18.00%
Commercial loans		$ 1,799,665,000		$ 1,101,282,000	$ 1,799,665,000		$ 1,101,282,000
Loans, net of unearned income		1,799,665,000		1,101,282,000	1,799,665,000		1,101,282,000
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		100,242,000		84,412,000	100,242,000		84,412,000
Average balance of impaired loans		67,341,000		78,181,000	64,065,000		87,439,000
Interest income recognized on impaired loan		276,000		201,000	566,000		445,000
Commercial loans		$ 11,233,278,000		9,634,349,000	11,233,278,000		9,634,349,000
Time period of default probability		1 year
Allowance - purchased credit impaired loans		$ 2,291,000		2,413,000	2,291,000		2,413,000
Credit Card & Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		13,275,000		17,452,000	13,275,000		17,452,000	$ 13,580,000	14,730,000	$ 13,061,000	$ 7,484,000
Loans, net of unearned income		345,544,000		348,429,000	345,544,000		348,429,000		358,131,000
Provision/(provision credit) for loan losses		4,697,000		7,273,000	6,590,000		15,930,000
Allowance - purchased credit impaired loans		$ 0		1,000	$ 0		1,000
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		$ 185,207,000		187,588,000	$ 185,207,000		187,588,000
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		$ 66,400,000		84,400,000	$ 66,400,000		84,400,000		$ 76,800,000
Finance And Insurance Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage contributed in total loan		12.00%			12.00%
Concentration risk, percentage					21.00%
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		39.00%			39.00%
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		$ 126,000		0	$ 126,000		0
Lowest expected default probability | number		1			1
PD Grade 12
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		$ 2,704,000		1,857,000	$ 2,704,000		1,857,000
PD Grade 13
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		4,944,000		$ 6,435,000	4,944,000		$ 6,435,000
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] June 30, 2015 includes $28.3 million of held-to-maturity consumer mortgage loans secured by residential real estate in process of foreclosure.

[2] (a) Balances as of June 30, 2015 and 2014, and December 31, 2014 include $ 66 .4 million, $ 84.4 million, and $ 76.8 million of restricted real estate loans, respectively. See Note 13 - Variable Interest Entities for additional information.