Loans (Narrative) (Details)	3 Months Ended			12 Months Ended
	Mar. 31, 2017 USD ($) number		Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)		Sep. 16, 2016 USD ($)	Dec. 31, 2015 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructurings loans	$ 270,000,000			$ 285,200,000
Allowance for loan losses	201,968,000		$ 204,034,000	202,068,000			$ 210,242,000
Average balance of impaired loans	291,167,000		310,405,000	310,368,000
Interest income recognized on impaired loan	1,733,000		1,467,000	6,779,000
Loans, net of unearned income	19,090,074,000	[1]	17,574,994,000	19,589,520,000	[1]
Provision for loan losses	(1,000,000)		3,000,000
Allowance - purchased credit impaired loans	590,000		1,148,000	700,000
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	123,995,000			123,250,000
Commercial loans	13,877,307,000			14,283,610,000
Allowance - purchased credit impaired loans	240,000			319,000
As Acquired | GE Capital Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans acquired						$ 537,400,000
Permanent Mortgage Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	$ 15,893,000		18,754,000	16,289,000			18,947,000
TDR, reduction of interest rate by increment, basis points	0.25%
TDRS Maturities	40 years
Loans, net of unearned income	$ 409,235,000		442,791,000	423,125,000
Modified interest rate increase	1.00%
Provision for loan losses	$ (816,000)		(860,000)
Allowance - purchased credit impaired loans	0		0
Loans Held-For-Sale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructurings loans	$ 67,200,000			69,300,000
Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	25.00%
Consumer Real Estate Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	23.00%
Allowance for loan losses	$ 49,680,000		67,321,000	50,357,000			80,614,000
TDRS Maturities	30 years
Loans, net of unearned income	$ 4,456,811,000	[2]	4,690,230,000	4,523,752,000	[2]
Provision for loan losses	(2,504,000)		(12,102,000)
Allowance - purchased credit impaired loans	350,000		725,000
Allowance For TDRs To Recorded Investment Of TDRs
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructurings loans	$ 43,400,000			$ 44,900,000
Ratio of the allowance for loan losses to loans	16.00%			16.00%
Loans To Mortgage Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 1,528,982,000			$ 2,045,189,000
Loans To Mortgage Companies | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage contributed in total loan	8.00%
Percentage of commercial & industrial loan portfolio	13.00%
Commercial loans	$ 1,528,982,000			2,045,189,000
Credit Card & Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	12,400,000		11,446,000	12,172,000			$ 11,885,000
Loans, net of unearned income	346,721,000		354,221,000	359,033,000
Provision for loan losses	2,872,000		2,080,000
Allowance - purchased credit impaired loans	$ 0		$ 1,000
Credit Card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Credit card workout program, granted rate reduction	0.00%
Loans, net of unearned income	$ 184,971,000			191,651,000
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%
Modified interest rate increase	2.00%
Restricted And Secured Consumer Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 32,500,000			35,900,000
Finance And Insurance Companies | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage contributed in total loan	13.00%
Percentage of commercial & industrial loan portfolio	22.00%
Commercial loans	$ 2,600,000,000
Finance Insurance And Loans To Mortgage Companies | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of commercial & industrial loan portfolio	35.00%
Maximum | Commercial Portfolio Segment [Member]
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 [Member]
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%
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%
Modified interest rate time period	5 years
Pass | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | number	12
Pass | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | number	1
Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | number	13
Special Mention | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | number	13
Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | number	14
Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | number	15
Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | number	16
Loss | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | number	16
PD Grade 1
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lowest expected default probability | number	1
PD Grade 1 | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	$ 78,000			77,000
PD Grade 12 | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	6,862,000			6,377,000
PD Grade 13 | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	3,757,000			$ 4,225,000
PD Grade 13 | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans	$ 500,000
LGD Grade 1 | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | number	1
LGD Grade 12 | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades | number	12
Loan Reassessed | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loans	$ 1,000,000

[1] March 31, 2017 and December 31, 2016 include $30.3 million and $28.5 million, respectively, of held-to-maturity consumer mortgage loans se cured by residential real estate properties in process of foreclosure.

[2] Balances as of March 3 1 , 201 7 and December 31, 201 6 , include $ 32 . 5 million and $ 35 . 9 million of restricted real estate loans, respectively. See Note 13 - Variable Interest Entities for additional information.