Corporate Share Repurchase [Abstract]

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- Definition

Employee Stock Purchase Plan [Abstract]

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Final price paid per share for the purchase of the targeted number of shares, determined by an average market price over a fixed period of time.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Amount of cost to be recognized for option under share-based payment arrangement.

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Amount of cash inflow from issuance of shares under share-based payment arrangement. Includes, but is not limited to, option exercised.

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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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The highest quantity of shares an employee can purchase under the plan per period.

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- Definition

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

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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.

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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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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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Purchase price of common stock expressed as a percentage of its fair value.

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Amount of stock repurchase plan authorized.

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Period which shares may be purchased under a stock repurchase plan authorized by an entity's Board of Directors, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount remaining of a stock repurchase plan authorized.

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Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Stockholders' Equity - Narrative (Details) - USD ($)	1 Months Ended			12 Months Ended
Stockholders' Equity - Narrative (Details) - USD ($)	Jun. 30, 2019	May 31, 2018	Sep. 30, 2015	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Sep. 11, 2019	Jan. 23, 2019	Sep. 30, 2016
Corporate Share Repurchase
Shares repurchased in period (shares)		260,000		4,122,133	782,248	14,000
Price per share of shares repurchased (USD per share)		$ 191.14
Stock repurchase program, authorized amount							$ 500,000,000.0	$ 350,000,000.0	$ 200,000,000.0
Stock repurchase program, period in force			3 years
Stock repurchase program, remaining authorized repurchase amount				$ 326,800,000
Shares repurchased in period				$ 448,433,000	$ 127,481,000	$ 1,966,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value per share of stock options (USD per share)				$ 48.65	$ 58.85	$ 53.17
Intrinsic value of options exercised				$ 10,400,000	$ 51,900,000	$ 13,300,000
Cash received from options exercised				2,600,000	$ 19,800,000	$ 4,700,000
Unrecognized compensation cost				$ 23,200,000
Weighted-average period in which cost is expected to be recognized				2 years 4 months 24 days
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average period in which cost is expected to be recognized				1 year 6 months
Unrecognized compensation cost, restricted stock				$ 11,200,000
2002 Stock Incentive Plan \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase the number of shares under the 2002 Stock Incentive Plan (shares)	800,000
Shares available for future option grants (shares)				900,000
Amended ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future option grants (shares)				59,263
Employee Stock Purchase Plan
Shares allowed to purchase in employee stock purchase plan per employee (shares)				1,250
Proportion of fair market value of common stock at which stock is purchased under ESPP (as a percent)				85.00%
Common stock issued under amended ESSP (shares)				4,745	3,386	3,061