Loans (Narrative) (Details)		3 Months Ended			6 Months Ended
		Jun. 30, 2017 USD ($) grade		Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) grade		Jun. 30, 2016 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)		Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income		$ 19,989,319,000	[1]	$ 18,589,337,000	$ 19,989,319,000	[1]	$ 18,589,337,000		$ 19,589,520,000	[1]
Allowance - purchased credit impaired loans		530,000		827,000	530,000		827,000		700,000
Provision credit for Loan and Lease Losses		100,000		400,000	200,000		300,000
Troubled debt restructurings loans		252,700,000			252,700,000				285,200,000
Less: Allowance for loan losses		197,257,000		199,807,000	197,257,000		199,807,000	$ 201,968,000	202,068,000		$ 204,034,000	$ 210,242,000
Average balance of impaired loans		274,444,000		316,045,000	282,802,000		313,222,000
Interest income recognized on impaired loan		1,679,000		1,701,000	3,411,000		3,138,000
Provision for loan losses		(2,000,000)		4,000,000	(3,000,000)		7,000,000
Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans		14,810,215,000			14,810,215,000				14,283,610,000
Allowance - purchased credit impaired loans		146,000			146,000				319,000
Less: Allowance for loan losses		122,849,000			122,849,000				123,250,000
Permanent Mortgage Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income		408,095,000		439,014,000	408,095,000		439,014,000		423,125,000
Allowance - purchased credit impaired loans		0		0	0		0
Less: Allowance for loan losses		$ 16,398,000		17,600,000	$ 16,398,000		17,600,000	15,893,000	16,289,000		18,754,000	18,947,000
TDR, reduction of interest rate by increment, basis points		0.25%			0.25%
TDRS Maturities					40 years
Modified interest rate increase		1.00%			1.00%
Provision for loan losses		$ 860,000		(1,289,000)	$ 44,000		(2,149,000)
Loans Held-For-Sale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructurings loans		66,100,000			$ 66,100,000				69,300,000
Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage					24.00%
Consumer Real Estate Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income		4,417,459,000	[2]	4,640,779,000	$ 4,417,459,000	[2]	4,640,779,000		4,523,752,000	[2]
Concentration risk, percentage					22.00%
Allowance - purchased credit impaired loans		384,000		336,000	$ 384,000		336,000
Less: Allowance for loan losses		46,069,000		59,081,000	$ 46,069,000		59,081,000	49,680,000	50,357,000		67,321,000	80,614,000
TDRS Maturities					30 years
Provision for loan losses		(4,803,000)		(7,740,000)	$ (7,307,000)		(19,842,000)
Allowance For TDRs To Recorded Investment Of TDRs
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructurings loans		$ 42,100,000			$ 42,100,000				$ 44,900,000
Ratio of the allowance for loan losses to loans		17.00%			17.00%				16.00%
Loans To Mortgage Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income		$ 2,092,762,000			$ 2,092,762,000				$ 2,045,189,000
Loans To Mortgage Companies | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans		$ 2,092,762,000			$ 2,092,762,000				2,045,189,000
Percentage of commercial & industrial loan portfolio		17.00%			17.00%
Percentage contributed in total loan		10.00%			10.00%
Credit Card And Other Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income		$ 353,550,000		360,687,000	$ 353,550,000		360,687,000		359,033,000
Allowance - purchased credit impaired loans		0		0	0		0
Less: Allowance for loan losses		11,941,000		11,890,000	11,941,000		11,890,000	$ 12,400,000	12,172,000		$ 11,446,000	$ 11,885,000
Provision for loan losses		1,944,000		$ 2,897,000	4,816,000		$ 4,977,000
Credit Card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income		$ 185,028,000			$ 185,028,000				191,651,000
Credit card workout program, granted rate reduction		0.00%			0.00%
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%
Modified interest rate increase		2.00%			2.00%
Restricted And Secured Consumer Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income		$ 28,800,000			$ 28,800,000				35,900,000
Finance And Insurance Companies | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans		$ 2,700,000,000			$ 2,700,000,000
Percentage of commercial & industrial loan portfolio		22.00%			22.00%
Percentage contributed in total loan		14.00%			14.00%
Finance Insurance And Loans To Mortgage Companies | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of commercial & industrial loan portfolio		39.00%			39.00%
TRUPs
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income		$ 307,373,000	[3]		$ 307,373,000	[3]			307,445,000	[4]
Valuation allowance		25,500,000			25,500,000				25,500,000
TRUPs | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans	[5]	307,373,000			307,373,000				307,445,000
Valuation allowance		$ 25,500,000			$ 25,500,000				25,500,000
Maximum | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forbearance agreements time period					12 months
Maximum | Permanent Mortgage Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Modified interest rate time period					5 years
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 | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forbearance agreements time period					6 months
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%
Modified interest rate time period					5 years
Pass | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | grade		12			12
Pass | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | grade		1			1
Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | grade		13			13
Special Mention | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | grade		13			13
Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | grade		14			14
Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | grade		15			15
Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | grade		16			16
Loss | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | grade		16			16
PD Grade 1
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lowest expected default probability | grade		1			1
PD Grade 1 | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less: Allowance for loan losses		$ 93,000			$ 93,000				77,000
PD Grade 12 | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less: Allowance for loan losses		7,684,000			7,684,000				6,377,000
PD Grade 13 | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less: Allowance for loan losses		3,821,000			3,821,000				$ 4,225,000
PD Grade 13 | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans		$ 500,000			$ 500,000
LGD Grade 1 | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | grade		1			1
LGD Grade 12 | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | grade		12			12
Loan Reassessed | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans		$ 1,000,000			$ 1,000,000

[1] June 30, 2017 and December 31, 2016 include $28.8 million and $28.5 million, respectively, of held-to-maturity consumer mortgage loans secured by residential real estate properties in process of foreclosure.

[2] Balances as of June 30, 2017 and December 31, 2016, include $28.8 million and $35.9 million of restricted real estate loans, respectively. See Note 13—Variable Interest Entities for additional information.

[3] TRUPS is presented net of the valuation allowance of $25.5 million.

[4] TRUPS is presented net of the valuation allowance of $25.5 million.

[5] Balances as of June 30, 2017 and December 31, 2016, presented net of a $25.5 million valuation allowance. Based on the underlying structure of the notes, the highest possible internal grade is “13”.