Summary Of Significant Accounting Policies (Narrative) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary Of Significant Accounting Policies [Line Items]
Cash equivalents	$ 531.8	$ 381.6
Provision to accounts receivable		$ 2.7
Anti-dilutive options to purchase common shares	0.4	1.3	0.7
Compensation cost recognized for stock-based awards	$ 5.3	$ 7.7	$ 6.4
Income tax benefit recognized in the income statement for stock-based awards	1.1	$ 3.1	$ 2.6
Weighted-average fair value per option granted		$ 8.76	$ 9.91
Total cash received as a result of stock option exercises	18.8	$ 2.0	$ 18.9
Tax benefit realized as a result of stock option exercises and the vesting of other share-based awards	3.7	2.1	2.9
Total intrinsic value of stock options exercised	5.1	0.7	3.7
Exchange losses related to foreign currency transactions	$ 0.5	$ 2.3	$ 1.3
Minimum [Member] \| Buildings And Building Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful lives of the assets	5 years
Minimum [Member] \| Machinery And Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful lives of the assets	2 years
Minimum [Member] \| Furniture And Fixtures [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful lives of the assets	2 years
Minimum [Member] \| Vehicles [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful lives of the assets	2 years
Maximum [Member] \| Buildings And Building Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful lives of the assets	40 years
Maximum [Member] \| Machinery And Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful lives of the assets	10 years
Maximum [Member] \| Furniture And Fixtures [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful lives of the assets	10 years
Maximum [Member] \| Vehicles [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful lives of the assets	5 years

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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.

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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Amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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Disclosure of the aggregate tax benefit realized from the exercise of stock options and the conversion of similar instruments during the annual period.

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Amount before tax of foreign currency transaction realized and unrealized loss recognized in the income statement.

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The total cash inflow associated with the amount received from holders to acquire the entity's shares under incentive and share awards, including stock option exercises. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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Amount of expense related to write-down of receivables to the amount expected to be collected. Includes, but is not limited to, accounts receivable and notes receivable.

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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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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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