The increase (decrease) during the reporting period in the aggregate amount of expenses incurred.

No definition available.

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Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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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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- References

No definition available.

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Stock-Based Compensation, Stock-Based Award Plan Activity (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Share-based Compensation Arrangement [Abstract]
Stock-based compensation expense	$ 6.0	$ 1.8	$ 13.6	$ 5.2
Accrued liabilities	251.5		251.5		$ 248.5
Stock Options [Member]
Share-based Compensation Arrangement [Abstract]
Unrecognized compensation expense	35.0		35.0
Restricted Stock Awards [Member]
Share-based Compensation Arrangement [Abstract]
Unrecognized compensation expense	35.0		35.0
2013 Stock Incentive Plan [Member] \| Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement [Abstract]
Accrued liabilities	$ 11.2		11.2
2013 and 2017 Plan [Member] \| Former Employee [Member]
Share-based Compensation Arrangement [Abstract]
Stock-based compensation expense			0.7
2013 and 2017 Plan [Member] \| Equity Awards [Member]
Share-based Compensation Arrangement [Abstract]
Stock-based compensation expense			5.0
2013 and 2017 Plan [Member] \| Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement [Abstract]
Increase in liability			$ 7.9