Share based compensation arrangement, number of share based compensation Plans.

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
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- Definition

Aggregate number of common shares reserved for future issuance.

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-Publisher FASB
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- Definition

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

+ References

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

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

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- Definition

Unrecognized cost of unvested options awarded to employees as compensation.

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- Definition

Amount of tax benefit from exercise of stock options granted under share-based compensation arrangement.

+ References

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- Definition

Amount of cash inflow from issuance of shares under share-based compensation arrangement, excluding stock option exercises.

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- Definition

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

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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

Discount rate from fair value on offering date that participants pay for 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.

+ References

No definition available.

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- Definition

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).

+ References

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- Definition

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.

+ References

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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

Number of share instruments newly issued under a share-based compensation plan.

+ References

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- Definition

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

+ References

No definition available.

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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 (Narrative) (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) ShareBasedCompensationPlan $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares	May 20, 2010 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity participation plans \| ShareBasedCompensationPlan	2
Weighted-average fair value of options granted \| $ / shares	$ 23.88	$ 19.19	$ 24.75
Total intrinsic value for options exercised	$ 37,200	$ 36,800	$ 33,000
Cash received from option exercises	56,500	27,400	25,400
Tax benefit realized from stock option exercises	$ 0	0	0
Share price \| $ / shares	$ 163.36
Total fair value of shares vested	$ 21,400	18,500	15,100
Non-cash compensation expense	38,249	32,915	28,747
Non-cash compensation capitalized to fixed and intangible assets	600	500	500
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost related to unvested stock options	$ 39,800
Weighted average period to recognize cost	2 years 6 months
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average period to recognize cost	2 years 7 months 6 days
Total unrecognized compensation expense related to unvested restricted stock	$ 24,400
2010 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum issuance of granted \| shares	7,500,000
Shares remaining available for future issuance under the plan \| shares	6,600,000
2010 Plan [Member] \| Class A Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum issuance of shares \| shares	15,000,000			15,000,000
Shares remaining available for future issuance under the plan \| shares	7,500,000
2008 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares remaining available for future issuance under the plan \| shares	244,942
Percentage of purchase plan price per share equal to the fair market value	85.00%
Non-cash compensation expense	$ 600	$ 500	$ 500
2008 Plan [Member] \| Class A Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum issuance of shares \| shares	500,000
Class A common stock were issued under the purchase plan \| shares	28,232	31,165
Cash proceeds from issuance of shares under the purchase plan	$ 3,300	$ 2,700
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual life of options and restricted stock units	7 years
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual life of options and restricted stock units	10 years