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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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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The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The risk-free interest rate assumption that is used in valuing an option on its own shares.

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

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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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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

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Amount of stock repurchase plan authorized.

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Common Stock and Stock-Based Compensation - Narrative (Details) - USD ($)		3 Months Ended
	Aug. 04, 2015	Mar. 31, 2018	Mar. 31, 2017	Aug. 09, 2017	Aug. 09, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase program, authorized amount				$ 100,000,000	$ 75,000,000.0
Award vesting period		4 years
Option grants in period (in shares)		631,625	810,650
Weighted average exercise price per option (in dollars per share)		$ 59.14	$ 84.92
Weighted average grant date fair value of options granted (in dollars per share)		$ 26.58	$ 33.56
Volatility		43.76%	37.27%
Expected dividend yield		0.00%	0.00%
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares authorized for grant (in shares)	500,000
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instrument other than options granted in period (in shares)		64,080	0
Weighted average grant date fair value of equity instruments other than options (in dollars per share)		$ 59.14
PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instrument other than options granted in period (in shares)		127,080	0
Weighted average grant date fair value of equity instruments other than options (in dollars per share)		$ 90.19
Risk free interest rate		2.06%
Volatility		47.00%
Expected term (in years)		3 years
Expected dividend yield		0.00%