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Employee Stock Purchase Plan (ESPP), Weighted Average Purchase Price of Shares Purchased

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Share-Based Compensation Arrangement By Share-Based Payment Award, Accelerated Vesting Awards, Number Of Key Employees

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Share-Based Compensation Arrangement By Share-Based Payment Award, Award Vesting Rights, Accelerated Vesting Awards

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Face (par) amount of the original debt instrument that was repurchased.

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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 cash inflow from issuance of shares under share-based payment arrangement. Excludes option exercised.

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The cash outflow from the repayment of a long-term debt instrument which can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder.

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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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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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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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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.

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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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Number of shares issued during the period as a result of an employee stock purchase plan.

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Amount of stock repurchase plan authorized.

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Amount remaining of a stock repurchase plan authorized.

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Stockholders' Equity - Additional Information (Details)	1 Months Ended		12 Months Ended
Stockholders' Equity - Additional Information (Details)	Aug. 31, 2018	Mar. 31, 2018	Dec. 31, 2020 USD ($) employee $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Jun. 30, 2020 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase program, authorized amount						$ 500,000,000.0
Repayments of convertible senior notes			$ 303,967,000	$ 0	$ 0
Remaining under repurchase program			350,400,000
Share-based compensation expense			$ 84,055,000	$ 64,909,000	$ 52,030,000
Stock issued under ESPP (in shares) \| shares			173,992	201,581	253,301
Weighted average purchase price of shares purchased (in dollars per share) \| $ / shares			$ 38.85	$ 25.55	$ 15.77
Exercises in period, intrinsic value			$ 53,500,000	$ 90,800,000	$ 57,200,000
0.25% Convertible Senior Notes Due 2023 \| Shares related to convertible senior notes
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Repurchased principal amount			57,400,000
Repayments of convertible senior notes			149,600,000
Extinguishment Of Aggregate Principal Amount \| 0.25% Convertible Senior Notes Due 2023 \| Shares related to convertible senior notes
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Repurchased principal amount			57,400,000
Aggregate consideration for principal amount exchanged			$ 149,600,000
Restricted Stock Units (RSUs) \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of stock awards			3 years
Restricted Stock Units (RSUs) \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of stock awards			4 years
Performance-based restricted stock units \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of stock awards			2 years
Performance-based restricted stock units \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of stock awards			3 years
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from issuance of shares under ESPP			$ 6,800,000	$ 5,100,000	$ 4,000,000.0
RSUs and PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense			$ 2,400,000
Accelerated vesting awards (in shares) \| shares			42,982
Accelerated vesting awards, number of key employees \| employee			3
Unrecognized compensation costs related to restricted stock units			$ 110,300,000
Weighted average vesting period for recognition of compensation expense			1 year 9 months 18 days
Performance based restricted stock unit award granted weighted average grant date fair value (in dollars per share) \| $ / shares			$ 45.37	$ 37.56	$ 21.67
Total fair value of awards vested			$ 200,100,000	$ 222,300,000	$ 120,900,000
Performance based restricted stock unit award granted to executive officers (in shares) \| shares			2,593,745
March 2020 PSU Grants, 2013 Plan \| Performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of stock awards			3 years
2013 Plan \| Performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of stock awards				3 years
2019 Performance Period \| Performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance based restricted stock unit award granted weighted average grant date fair value (in dollars per share) \| $ / shares				$ 40.42
March 2019 PSU Grants \| Performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance based restricted stock unit award granted to executive officers (in shares) \| shares				436,042
March 2018 PSU Grants \| Performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of stock awards		3 years
Performance based restricted stock unit award granted weighted average grant date fair value (in dollars per share) \| $ / shares					$ 19.70
Performance based restricted stock unit award granted to executive officers (in shares) \| shares					845,934
2018 Performance Period \| Performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of stock awards	3 years
Performance based restricted stock unit award granted weighted average grant date fair value (in dollars per share) \| $ / shares					$ 28.74
Performance based restricted stock unit award granted to executive officers (in shares) \| shares					45,756
March 2020 PSU Grants \| Performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance based restricted stock unit award granted to executive officers (in shares) \| shares			460,976
A2020 Performance Period \| Performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance based restricted stock unit award granted weighted average grant date fair value (in dollars per share) \| $ / shares			$ 39.21