Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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-Publisher FASB
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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest exercisable or convertible options. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

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The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Retirement and Share-based Compensation Plans (Schedule of Stock Options Outstanding, By Exercise Price Range) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding and vested, aggregate intrinsic value	$ 12.9
Proceeds from stock options exercised	10.0	$ 14.0	$ 5.0
Stock Option Plans, All Stock Option Plans For Officers, Directors And Employees
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options exercised in period, total intrinsic value	$ 3.0	$ 1.5	$ 4.0
Exercise Price Range I
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit	$ 5.07
Exercise price range, upper range limit	$ 8.02
Stock options outstanding and vested, number of awards	122,500
Stock options outstanding and vested, remaining life (yrs)	4 months 11 days
Stock options outstanding and vested, weighted-average exercise price per share	$ 6.77
Exercise Price Range II
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit	9.27
Exercise price range, upper range limit	$ 11.35
Stock options outstanding and vested, number of awards	252,515
Stock options outstanding and vested, remaining life (yrs)	1 year 6 months 16 days
Stock options outstanding and vested, weighted-average exercise price per share	$ 9.97
Exercise Price Range III
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit	12.04
Exercise price range, upper range limit	$ 24.79
Stock options outstanding and vested, number of awards	846,850
Stock options outstanding and vested, remaining life (yrs)	1 year 10 months 3 days
Stock options outstanding and vested, weighted-average exercise price per share	$ 21.17
Exercise Price Range, All Options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit	5.07
Exercise price range, upper range limit	$ 24.79
Stock options outstanding and vested, number of awards	1,221,865
Stock options outstanding and vested, remaining life (yrs)	1 year 7 months 18 days
Stock options outstanding and vested, weighted-average exercise price per share	$ 17.41