Fair value of the assets less the liabilities of a derivative or group of derivatives.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
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-Section 50
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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
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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.

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No definition available.

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Cash receipts from customers during the current period which are usually for sales of goods and services.

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-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
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DERIVATIVES - Derivative Reflected in the Balance Sheet (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	May 23, 2016
Rowan Relentless [Member]
Derivatives, Fair Value [Line Items]
Contingent payment derivative, fair value					$ 6.2
Freeport-McMoRan [Member]
Derivatives, Fair Value [Line Items]
Proceeds from contingent payment provision settlement	$ 6.0
Recurring [Member]
Derivatives, Fair Value [Line Items]
Contingent payment derivative, fair value			$ 0.0
Other Expense [Member]
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net		$ 0.0	$ (0.1)	$ (0.1)