Share-Based Payments - Narrative (Details)	3 Months Ended
Mar. 31, 2019 USD ($) incentive_program	Mar. 31, 2018 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
General vesting period	3 years
Number of incentive programs \| incentive_program	2
Total unrecognized compensation cost related to unvested share-based payments	$ 83,000,000.0
Weighted-average period for unrecognized compensation cost expected to be recognized	2 years
Proceeds from exercise of stock options	$ 0	$ 0
Stock Options \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of stock option expiration from date of grant	10 years

Number of Incentive Programs

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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Publisher FASB
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- Definition

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.

+ References

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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.

+ References

No definition available.

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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