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- Definition

CashReceivedFromProceedsByParticipants

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- Definition

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- Definition

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- Definition

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- Definition

ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedAggregatePurchaseValue

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- Definition

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ShareBasedCompensationArrangementByShareBasedPaymentAwardSubscriptionPeriodEnding

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ThresholdPeriodWorkedPerWeekByEmployees

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- Definition

ValueOfOneYearStockOptionPercentage

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No definition available.

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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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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

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).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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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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- Definition

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

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No definition available.

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- Definition

Number of suspense shares held by the Employee Stock Option Plan at balance sheet date. Suspense shares are shares that have not been released, committed to be released or allocated to individual participant accounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=65895303&loc=d3e17540-113929

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Stock Based Compensation Employee Stock Purchase Plan Details (Details)	12 Months Ended
	Dec. 31, 2017 USD ($) shares	Aug. 31, 2017 $ / shares	Jul. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) shares	Aug. 31, 2016 $ / shares	Jul. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) shares	Aug. 31, 2015 $ / shares	Jul. 31, 2015 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	0
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate	10.00%
Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	4,197,920
Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	4,151,251
ThresholdPeriodWorkedPerWeekByEmployees	20
AllottedValueMaximum \| $	$ 25,000
ShareBasedCompensationArrangementByShareBasedPaymentAwardSubscriptionPeriodBeginning	--08-01
ShareBasedCompensationArrangementByShareBasedPaymentAwardSubscriptionPeriodEnding	--07-31
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent	85.00%
ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentOfMarketPrice	15.00%
ValueOfOneYearStockOptionPercentage	85.00%
EstimatedFairValuePerShareOption \| $ / shares		$ 8.64			$ 7.61			$ 6.43
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period			529,012			514,665			539,389
ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedAggregatePurchaseValue \| $			$ 16,400,000			$ 15,000,000.0			$ 14,400,000
ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedAggregatePurchasePricePerShare \| $ / shares			$ 31.03			$ 29.23			$ 26.62
Shares held in Employee Stock Option Plan, Suspense Shares	217,514			247,023			231,803
CashReceivedFromProceedsByParticipants \| $	$ 8,200,000			$ 7,700,000			$ 6,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	17,000,000