Represents equivalent share deducted for every one share delivered.

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Number of performance period in performance based share program.

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Percentage of multiplication award by product.

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Represents share based compensation arrangement by share based payment award fair value assumptions expected forfeiture rate.

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No definition available.

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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-Section 50
-Paragraph 2
-Subparagraph (i)
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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The risk-free interest rate assumption that is used in valuing an option on its own shares.

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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

Number of additional shares authorized for issuance under an established share-based compensation plan.

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No definition available.

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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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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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition

Gross number of share options (or share units) granted during the period.

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No definition available.

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- Definition

Price of a single share of a number of saleable stocks of a company.

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- Definition

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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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Weighted average remaining contractual term for fully vested and expected to vest exercisable or convertible options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. 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.

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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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Accounting for Stock-based Compensation - Additional Information (Details)		3 Months Ended	12 Months Ended
	Jun. 05, 2015 shares	Mar. 31, 2015 PerformancePeriod	Dec. 31, 2017 USD ($) PerformancePeriod $ / shares shares	Dec. 31, 2016 USD ($) PerformancePeriod shares	Dec. 31, 2015 USD ($) PerformancePeriod shares	Jun. 04, 2015 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, options, outstanding, weighted average remaining contractual term			5 years
Performance based share awards, performance period			3 years
Share-based compensation arrangement by share-based payment award, options, vested in period, fair value \| $			$ 1,900,000	$ 1,300,000	$ 2,000,000
Share-based compensation arrangement by share-based payment award, options, vested and expected to vest, exercisable, weighted average remaining contractual term			5 years
Share-based compensation arrangement by share-based payment award, options, exercisable, weighted average remaining contractual term			5 years
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, fair value assumptions, expected forfeiture rate			1.86%
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, fair value assumptions, expected forfeiture rate			19.51%
Options, Restricted Stock and RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares available for grant \| shares	5,966,186
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, options, outstanding, weighted average remaining contractual term			10 years
Share-based compensation arrangement by share-based payment award, options, grants in period, gross \| shares			0	0	0
Share price \| $ / shares			$ 52.50
Share-based compensation arrangement by share-based payment award, options, exercises in period, intrinsic value \| $			$ 4,500,000	$ 2,500,000	$ 800,000
Employee Stock Option \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based share awards, performance period			3 years
Employee Stock Option \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based share awards, performance period			4 years
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share price \| $ / shares			$ 52.50
Share-based compensation arrangement by share-based payment award, equity instruments other than options, vested in period, fair value \| $			$ 6,300,000	7,200,000	6,300,000
Restricted Stock Units (RSUs) \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based share awards, performance period			3 years
Restricted Stock Units (RSUs) \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based share awards, performance period			4 years
Cash Settled RSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based share awards, performance period			4 years
Share price \| $ / shares			$ 52.50
Share-based compensation arrangement by share-based payment award, equity instruments other than options, vested in period, fair value \| $			$ 6,900,000	$ 5,900,000	$ 2,900,000
Non-Employee Director Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Employee service share-based compensation, nonvested awards, compensation not yet recognized, share-based awards other than options \| $			$ 0
Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share price \| $ / shares			$ 52.50
Number of performance period in performance based share program \| PerformancePeriod		2	1	2	3
Percentage of multiplication award by product			2.00%
Share-based compensation arrangement by share-based payment award, fair value assumptions, expected dividend rate			0.00%	0.00%	0.00%
Share-based compensation arrangement by share-based payment award, fair Value assumptions, expected volatility rate			31.30%	30.90%	29.30%
Share-based compensation arrangement by share-based payment award, fair value assumptions, risk free interest rate			1.50%	1.00%	1.00%
Omnibus Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of additional shares authorized \| shares	1,540,000
Share-based compensation arrangement by share-based payment award, number of shares authorized \| shares	5,090,000					3,550,000
Share-based compensation arrangement by share-based payment award, number of shares available for grant \| shares			1,900,000
Equivalent share deducted for every one share delivered	1.93