Accumulated Other Comprehensive Income (Loss) (AOCI Reclass to IS) (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Salaries and Benefits	$ (49,780)us-gaap_LaborAndRelatedExpense	$ (46,897)us-gaap_LaborAndRelatedExpense
Income Before Provision for Income Taxes	62,162	54,454
Tax Benefit (Expense)	(19,720)us-gaap_IncomeTaxExpenseBenefit	(15,862)us-gaap_IncomeTaxExpenseBenefit
Net Income	42,442us-gaap_NetIncomeLoss	38,592us-gaap_NetIncomeLoss
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Net Income	(238)	46
Amortization of Unrealized Gains(Losses) of Investment Securities Transferred from AFS to HTM \| Reclassification out of Accumulated Other Comprehensive Income
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Interest Income	(30)	333
Tax Benefit (Expense)	12	(131)
Net Income	(18)	202
Amortization of Defined Benefit Pension Items \| Reclassification out of Accumulated Other Comprehensive Income
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Income Before Provision for Income Taxes	(362)	(258)
Tax Benefit (Expense)	142	102
Net Income	(220)	(156)
Prior Service Credit \| Reclassification out of Accumulated Other Comprehensive Income
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Salaries and Benefits	81	81
Net Actuarial Losses \| Reclassification out of Accumulated Other Comprehensive Income
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Salaries and Benefits	$ (443)	$ (339)

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Sum of operating profit and nonoperating income or expense before Income or Loss from equity method investments, income taxes, extraordinary items, and noncontrolling interest.

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- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount before accretion (amortization) of purchase discount (premium) of interest income on nonoperating securities.

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- Definition

The aggregate amount of expenditures for salaries, wages, profit sharing and incentive compensation, and other employee benefits, including equity-based compensation, and pension and other postretirement benefit expense.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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