Number of common stock trading days.

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- Definition

Period of Time to Measure Company Total Shareholder Return and Apply Vesting Payout Cap

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No definition available.

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- Definition

Share-based Compensation Arragement by Share-based Payment Award, Equity Instruments Other than Options, Payout Potential Range

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No definition available.

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Payout Potential Cap

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No definition available.

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- Definition

Share based compensation arrangement by share based payment award options exercisable rate.

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No definition available.

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- Definition

weighted average period for unvested share-based RSUs to be recognized

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No definition available.

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- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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-Section 50
-Paragraph 1
-Subparagraph (b)
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

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No definition available.

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- Definition

Unrecognized cost of unvested options awarded to employees as compensation.

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No definition available.

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- Definition

The aggregate cash inflow comprised of the amount received from (a) employees to acquire the entity's shares under incentive awards, including stock option exercises and restricted stock arrangements, and (b) the excess tax benefit arising from such transactions.

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No definition available.

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- Definition

The cash inflow associated with the amount received from holders exercising their stock options. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (j)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Paragraph 14
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-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3255-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

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- Definition

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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- Definition

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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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of fully vested and expected to vest options that are exercisable.

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- Definition

Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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Stock-Based Compensation Plans (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting payout cap	100.00%
Period of time to measure Company total shareholder return and apply vesting payout cap	3 years
Weighted-average fair value of options granted during period	$ 12.98	$ 6.52	$ 9.80
Fair value of shares vested	$ 6.3	$ 7.8	$ 9.0
Total intrinsic value of options exercised	16.9	14.8	7.9
Cash received from options exercised	25.2	26.4	8.9
Proceeds and Excess Tax Benefit from Share-based Compensation		0.4	1.6
Aggregate intrinsic value of exercisable options	29.9	15.8	2.1
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options	10.2
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options	$ 20.2
weighted average period for unvested share-based RSUs to be recognized	1.20
Stock Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock trading days	10 days
Cash received from options exercised	$ 31.2	31.8	11.9
Stock Compensation Plan [Member] \| Options Exercisable After First Year [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercisable rate	25.00%
Stock Compensation Plan [Member] \| Options Exercisable After Second Year [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercisable rate	50.00%
Stock Compensation Plan [Member] \| Options Exercisable After Third Year [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercisable rate	75.00%
Stock Compensation Plan [Member] \| Options Exercisable After Fourth Year [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercisable rate	100.00%
Restricted Stock And Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense recognized for restricted stock awards	$ 13.9	$ 13.8	$ 12.2
Restricted Stock And Restricted Stock Units [Member] \| Options Exercisable After First Year [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercisable rate	25.00%
Restricted Stock And Restricted Stock Units [Member] \| Options Exercisable After Second Year [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercisable rate	50.00%
Restricted Stock And Restricted Stock Units [Member] \| Options Exercisable After Third Year [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercisable rate	75.00%
Restricted Stock And Restricted Stock Units [Member] \| Options Exercisable After Fourth Year [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercisable rate	100.00%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting payout potential range	0.00%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting payout potential range	200.00%