Share-Based Payments - Narrative (Details)	6 Months Ended
Jun. 30, 2019 USD ($) incentive_program	Jun. 30, 2018 USD ($)
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 expense related to unvested share-based payments	$ 69,800,000
Weighted-average period for unrecognized compensation expense expected to be recognized	1 year 9 months 18 days
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

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- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

+ 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
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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- Definition

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.

+ References

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- Definition

Amount of cash inflow from exercise of option under share-based payment arrangement.

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 45
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- Definition

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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- 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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