Number Of Directors

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- Definition

-- None. No documentation exists for this element. --

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No definition available.

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- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

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

Unrecognized cost of unvested share-based compensation awards.

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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=109197908&loc=d3e5070-113901

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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.

+ References

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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.

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-Topic 718
-SubTopic 10
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-Paragraph 2
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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).

+ 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 (c)(2)(iii)(1)
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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).

+ 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

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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Stock-Based Compensation - Narrative (Details) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
	Feb. 15, 2018 $ / shares	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) director shares	Sep. 30, 2017 USD ($)
Stock-Based Compensation
Stock-based compensation expense		$ 2.8	$ 0.6	$ 8.8	$ 11.8
Unrecognized compensation cost and vesting period
Unrecognized compensation costs related to unvested share-based compensation arrangements		$ 12.4		$ 12.4
Weighted-average period for recognition of unrecognized stock-based compensation expense				2 years 2 months 30 days
Restricted Stock Units
Stock-Based Compensation
Awarded (in shares) \| shares				188,942
Weighted average granted date fair value (in dollars per share) \| $ / shares	$ 54.99
Vesting period	3 years
Directors \| Restricted Stock Units
Stock-Based Compensation
Number of directors \| director				8
Employees \| Restricted Stock Units
Stock-Based Compensation
Vesting period	4 years