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As of the balance sheet date, the number of shares related to the aggregate unrecognized cost of equity-based awards made to employees under equity-based compensation awards that have yet to vest.

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No definition available.

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As of the balance sheet date, the weighted average fair value of shares related to the aggregate unrecognized cost of equity-based awards made to employees under equity-based compensation awards that have yet to vest.

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Pertains to the percentage of the lower of the market related to purchase of common stock permitted by employee stock purchase plan to be acquired by employees and employees of designated subsidiaries.

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Aggregate number of common shares reserved for future issuance.

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Face amount or stated value per share of common stock.

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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

+ References

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Unrecognized cost of unvested share-based compensation awards.

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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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Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

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The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.

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Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.

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Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

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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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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

The highest percentage of annual salary that an employee is permitted to utilize with respect to the plan.

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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

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.

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- Definition

The remaining number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

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No definition available.

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Number of shares that have been repurchased and retired during the period.

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Total cost of shares repurchased divided by the total number of shares repurchased.

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Authorized shares of common and preferred stock and stock-based compensation plans - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions					3 Months Ended	12 Months Ended
	May 14, 2019	Jan. 23, 2019	May 12, 2015	May 14, 2013	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Oct. 23, 2019	May 11, 2010	May 31, 2005	Jan. 21, 2004
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional number of shares reserved for issuance (in shares)				180,000,000
Common stock, shares authorized (in shares)				360,000,000	360,000,000	360,000,000	360,000,000
Common and preferred stock shares authorized (in shares)				365,000,000
Preferred stock, shares authorized (in shares)				5,000,000	5,000,000	5,000,000	5,000,000
Preferred stock, par value (in dollars per share)				$ 0.01	$ 0.01	$ 0.01	$ 0.01
Common stock, par value (in dollars per share)				$ 0.01	$ 0.01	$ 0.01	$ 0.01
Preferred stock, shares issued (in shares)					0	0	0
Preferred stock, shares outstanding (in shares)					0	0	0
Common stock repurchased (in shares)		4,000,000			794,324	4,000,000	0
Common stock repurchased, average cost per share (in dollars per share)					$ 42.98	$ 42.83
Authorized common stock available for repurchase (shares)					3,000,000	3,000,000		3,000,000
Restricted Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved for issuance (in shares)									3,362,304
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense					$ 151.6	$ 151.6
Unrecognized stock-based compensation expense (in shares)						3,289,637
Unrecognized stock-based compensation expense, weighted average fair value (in dollars per share)						$ 40.99
Weighted average period for which unrecognized stock-based compensation expense recognized						2 years 10 months 20 days
Incentive Plan (2005)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved for issuance (in shares)										4,050,000
Award vesting period, (in years)						5 years
Incentive Plan (2005) \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period, (in years)						3 years
Incentive Plan (2005) \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period, (in years)						10 years
Incentive Plan (2010)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved for issuance (in shares)			2,518,416						3,000,000
Award vesting period, (in years)						5 years
Incentive Plan (2010) \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period, (in years)						3 years
Incentive Plan (2010) \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period, (in years)						10 years
Incentive Plan (2015)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional number of shares reserved for issuance (in shares)			3,000,000
Award vesting period, (in years)						5 years
Number of shares available for grant (in shares)					1,920,771	1,920,771
Incentive Plan (2015) \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period, (in years)						10 years
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional number of shares reserved for issuance (in shares)	3,000,000
Percentage of the lower of the market related to purchase of common stock					85.00%	85.00%
Maximum employee subscription rate					15.00%	15.00%
Shares of common stock reserved for future employee purchases (in shares)					4,085,770	4,085,770
Shares issued during the period (in shares)						909,274
Weighted average grant date fair value (in dollars per share)						$ 36.50
Authorized Preferred Stock And Preferred Stock Purchase Rights Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved for issuance (in shares)											750,000
Three year vesting period \| Incentive Plan (2015) \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period, (in years)						3 years
Four year vesting period \| Incentive Plan (2015)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period, (in years)						4 years
Five year vesting period \| Incentive Plan (2015)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period, (in years)						5 years
Ten year vesting period \| Incentive Plan (2015) \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period, (in years)						10 years