Aggregate number of common shares reserved for future issuance.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.29)

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Unrecognized cost of unvested share-based compensation awards.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

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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.

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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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Percentage of vesting of share-based compensation awards.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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 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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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

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

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-Name Accounting Standards Codification

-Topic 718

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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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-Publisher FASB

-Name Accounting Standards Codification

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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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-Publisher FASB

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Stock Compensation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted			1,754,170
Weighted-average fair value per share of stock-based awards, granted to employees	$ 23.20	$ 3.53	$ 22.50	$ 4.56
Intrinsic value of stock options exercised			$ 3.0
Grant date fair value of stock options that vested			0.6	2.7
Unrecognized compensation cost related to non-vested share-based compensation arrangements granted, including stock options and restricted stock	$ 45.3		$ 45.3
Unrecognized compensation costs expected to be recognized period			3 years 3 months 18 days
Performance
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted			459,500
Time-Based
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted			969,500
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available to be issued under the ESPP	250,000		250,000
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted shares			6,000
Grant date fair value of shares grant			$ 34.92
Stock Incentive, 2002 to December 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation granted under plan vest period			3 years
Underlying shares vesting on anniversary of grant			33.33%
Term of award			10 years
Stock Incentive Plan, 2011, Beginning in June 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock remain available for future grant under the 2011 Plan	3,199,747		3,199,747
Share based compensation granted under plan vest period			4 years
Stock Incentive Plan, 2011, Beginning in June 2011 \| Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available to be issued under the ESPP	250,000		250,000
Stock Incentive Plan, 2011, Beginning in June 2011 \| First Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Underlying shares vesting on anniversary of grant			25.00%
Stock Incentive Plan, 2011, Beginning in June 2011 \| Vesting Month After First Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Underlying shares vesting on anniversary of grant			2.50%
Amended and Restated 2011 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional shares available for grant			3,600,000