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- Definition

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.

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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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- Definition

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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- Definition

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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- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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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 share-based payment arrangement.

+ References

No definition available.

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Number of shares authorized for issuance under share-based payment arrangement.

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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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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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Number of shares issued under share-based payment arrangement.

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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.

+ References

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 (Details) - $ / shares		3 Months Ended		6 Months Ended
	May 14, 2013	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	May 08, 2020	Dec. 31, 2019	May 14, 2019	May 12, 2015	May 13, 2013	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, authorized (in shares)	360,000,000	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, authorized (in shares)		5,000,000		5,000,000			5,000,000			5,000,000
Preferred stock, par value per share (in usd per share)		$ 0.01		$ 0.01			$ 0.01			$ 0.01
Common stock, par value per share (in usd per share)		$ 0.01		$ 0.01			$ 0.01			$ 0.01
Number of shares reserved for issuance									2,518,416		3,362,304
Preferred stock, issued (in shares)		0		0			0
Preferred stock, outstanding (in shares)		0		0			0
Common stock repurchased (in shares)		503,326	1,114,500	668,199	2,149,598
Common stock repurchased, average cost per share		$ 34.08	$ 41.25	$ 35.44	$ 42.97
Authorized common stock available for repurchase (in shares)		2,331,801		2,331,801
Incentive Plan (2005) \| Restricted Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved for issuance												4,050,000
Incentive Plan (2005) \| Restricted Stock Plan \| One to three year vesting period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)				3 years
Incentive Plan (2005) \| Restricted Stock Plan \| Three to Five year vesting period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)				5 years
Incentive Plan (2005) \| Restricted Stock Plan \| Ten year vesting period
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									2,518,416
Incentive Plan (2010) \| Restricted Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, authorized (in shares)											3,000,000
Incentive Plan (2010) \| Restricted Stock Plan \| One to three year vesting period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)				3 years
Incentive Plan (2010) \| Restricted Stock Plan \| Three to Five year vesting period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)				5 years
Incentive Plan (2010) \| Restricted Stock Plan \| Ten year vesting period
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]
Number of shares reserved for issuance						567,142			3,000,000
Shares available for grant under 2015 restricted stock plan (in shares)						567,142
Incentive Plan (2015) \| Restricted Stock Plan \| One to three year vesting period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)				3 years
Incentive Plan (2015) \| Restricted Stock Plan \| Three to Five year vesting period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)				5 years
Incentive Plan (2015) \| Restricted Stock Plan \| Ten year vesting period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)				10 years
Incentive Plan (2015) \| Restricted Stock Plan \| Four year vesting period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)				4 years
Incentive Plan (2020)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved for issuance						4,500,000
Shares available for grant under 2015 restricted stock plan (in shares)		5,104,408		5,104,408
Incentive Plan (2020) \| Restricted Stock Plan \| One to three year vesting period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)				1 year
Incentive Plan (2020) \| Restricted Stock Plan \| Three to Five year vesting period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)				3 years
Incentive Plan (2020) \| Restricted Stock Plan \| Four year vesting period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)				4 years
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, authorized (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%
Common stock reserved for future issuance under employee stock purchase plan (in shares)		3,577,369		3,577,369
Shares issued under employee stock purchase plan (in shares)				508,401
Weighted average purchase price of employees' purchase rights (in usd per share)				$ 33.93
Series A Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, authorized (in shares)													750,000