Allowance for Loan Losses Schedule of Credit Losses Related to Originated Financing Receivables, Current (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014		Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Write-downs	$ 2,200
Provision for Loan, Lease, and Other Losses	8,248		14,536
Originated Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses	97,545		92,116		95,696		96,484
Financing Receivable, Allowance for Credit Losses, Write-downs	(8,567)		(13,160)
Financing Receivable, Allowance for Credit Losses, Recovery	4,380		5,138
Provision for Loan, Lease, and Other Losses	(6,036)		(3,654)
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	13,297		8,561		5,950
Impaired Financing Receivable, Related Allowance	13,297	[1]	8,561	[1]	5,950	[1]
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	84,248		83,555		89,746
Financing Receivable, Individually Evaluated for Impairment	110,943		99,104		93,448
Financing Receivable, Collectively Evaluated for Impairment	12,745,094		10,727,809		12,400,364
Financing Receivable, Net	12,856,037		10,826,913		12,493,812
Originated Loans | Commercial Portfolio Segmen
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses	39,838		40,175		37,375		42,981
Financing Receivable, Allowance for Credit Losses, Write-downs			(5,074)
Financing Receivable, Allowance for Credit Losses, Recovery			997
Provision for Loan, Lease, and Other Losses			(1,271)
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	10,042		2,866		72
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	29,796		37,309		37,303
Financing Receivable, Individually Evaluated for Impairment	35,792		7,143		11,759
Financing Receivable, Collectively Evaluated for Impairment	5,282,105		4,469,013		5,163,442
Financing Receivable, Net	5,317,897		4,476,156		5,175,201
Originated Loans | Commercial Real Estate Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses	8,813		13,385		10,492		12,265
Financing Receivable, Allowance for Credit Losses, Write-downs	(215)		(79)
Financing Receivable, Allowance for Credit Losses, Recovery	0		4
Provision for Loan, Lease, and Other Losses	1,464		(1,195)
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	317		2,918		2,914
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	8,496		10,467		7,578
Financing Receivable, Individually Evaluated for Impairment	15,000		31,576		23,300
Financing Receivable, Collectively Evaluated for Impairment	2,118,017		2,215,709		2,093,818
Financing Receivable, Net	2,133,017		2,247,285		2,117,118
Originated Loans | Commercial Construction Financing Receivable Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses	1,752		1,470		2,202		2,810
Financing Receivable, Allowance for Credit Losses, Write-downs	0		0
Financing Receivable, Allowance for Credit Losses, Recovery	1		28
Provision for Loan, Lease, and Other Losses	451		1,368
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	0		0		0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	1,752		1,470		2,202
Financing Receivable, Individually Evaluated for Impairment	0		404		0
Financing Receivable, Collectively Evaluated for Impairment	580,978		359,347		537,766
Financing Receivable, Net	580,978		359,751		537,766
Originated Loans | Finance Leases Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses	629		1,027		674		1,081
Financing Receivable, Allowance for Credit Losses, Write-downs	0		0
Financing Receivable, Allowance for Credit Losses, Recovery	4		0
Provision for Loan, Lease, and Other Losses	49		54
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	0		0		0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	629		1,027		674
Financing Receivable, Individually Evaluated for Impairment	0		0		0
Financing Receivable, Collectively Evaluated for Impairment	388,873		257,509		370,179
Financing Receivable, Net	388,873		257,509		370,179
Originated Loans | Installment Financing Receivable Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses	13,358		11,604		12,918		11,935
Financing Receivable, Allowance for Credit Losses, Write-downs	(5,055)		(4,584)
Financing Receivable, Allowance for Credit Losses, Recovery	3,020		2,749
Provision for Loan, Lease, and Other Losses	(2,475)		(1,504)
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment			1,006		1,178
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	12,353		10,598		11,740
Financing Receivable, Individually Evaluated for Impairment	26,882		25,818		24,905
Financing Receivable, Collectively Evaluated for Impairment	2,473,406		1,809,704		2,368,546
Financing Receivable, Net	2,500,288		1,835,522		2,393,451
Originated Loans | Home Equity Receivable Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses	19,433		13,160		19,324		12,900
Financing Receivable, Allowance for Credit Losses, Write-downs	(911)		(1,409)
Financing Receivable, Allowance for Credit Losses, Recovery	613		904
Provision for Loan, Lease, and Other Losses	(407)		(765)
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment			223		207
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	19,179		12,937		19,117
Financing Receivable, Individually Evaluated for Impairment	7,632		6,931		7,379
Financing Receivable, Collectively Evaluated for Impairment	1,126,606		939,871		1,102,957
Financing Receivable, Net	1,134,238		946,802		1,110,336
Originated Loans | Credit Card Receivables Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses	7,801		6,851		7,966		7,740
Financing Receivable, Allowance for Credit Losses, Write-downs	(1,452)		(1,455)
Financing Receivable, Allowance for Credit Losses, Recovery	366		418
Provision for Loan, Lease, and Other Losses	(921)		(148)
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment			307		296
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	7,538		6,544		7,670
Financing Receivable, Individually Evaluated for Impairment	815		1,034		854
Financing Receivable, Collectively Evaluated for Impairment	159,951		146,883		163,624
Financing Receivable, Net	160,766		147,917		164,478
Originated Loans | Residential Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses	5,921		4,444		4,745		4,772
Financing Receivable, Allowance for Credit Losses, Write-downs	(424)		(559)
Financing Receivable, Allowance for Credit Losses, Recovery	35		38
Provision for Loan, Lease, and Other Losses	(1,565)		(193)
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment			1,241	[1]	1,283	[1]
Impaired Financing Receivable, Related Allowance	1,416	[1]
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	4,505		3,203		3,462
Financing Receivable, Individually Evaluated for Impairment	24,822		26,198		25,251
Financing Receivable, Collectively Evaluated for Impairment	615,158		529,773		600,032
Financing Receivable, Net	639,980		555,971		625,283
Originated Loans | Commercial and Industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Write-downs	(510)
Financing Receivable, Allowance for Credit Losses, Recovery	341
Provision for Loan, Lease, and Other Losses	(2,632)
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment			2,866	[1]	72	[1]
Financing Receivable, Net	5,317,897		4,476,156		5,175,201
Total Tdr Allowance
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Related Allowance	5,661		9,074		6,645
Total Tdr Allowance | Originated Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Related Allowance	3,133		5,079		3,195
Total Tdr Allowance | Consumer Residential Mortgages Financing Receivable
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Related Allowance	1,416		1,241
Total Tdr Allowance | Consumer Installment
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Related Allowance	$ 1,053		$ 1,006		$ 1,243

[1] Note 1: These tables exclude loans fully charged off.Note 2: The differences between the recorded investment and unpaid principal balance amounts represent partial charge offs.