Equity Awards - RSU (Details) - Restricted stock and restricted stock units - $ / shares	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of restricted stock and restricted stock units activity
Beginning Balance (in shares)	737,950	716,128	727,100
Grants (in shares)	158,748	159,005	75,140
Vested (in shares)	(393,588)	(236,164)	(84,908)
Awards assumed through acquisition of CEC (in shares)		136,324
Forfeitures (in shares)	(34,160)	(37,343)	(1,204)
Ending Balance (in shares)	468,950	737,950	716,128
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested,Weighted Average Grant Date Fair Value [Roll Forward] [Roll Forward]
Beginning Balance, Weighted-average grant price (in dollars per share)	$ 114.43	$ 99.65	$ 97.53
Grants, Weighted-average grant price (in dollars per share)	128.87	93.30	82.18
Awards assumed through acquisition of CEC, Weighted-average grant price (in dollars per share)		118.29
Vested shares, Weighted-average grant price (in dollars per share)	141.75	76.78	66.60
Forfeitures, Weighted-average grant price (in dollars per share)	79.02	83.69	62.28
Ending Balance, Weighted-average grant price (in dollars per share)	$ 98.98	$ 114.43	$ 99.65

Number of share options (or share units) assumed through acquisition during the current period.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that awarded.

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No definition available.

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Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested,Weighted Average Grant Date Fair Value [Roll Forward] [Roll Forward]

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
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- Definition

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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- Definition

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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- Definition

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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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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- Definition

The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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