Acquisition (Selected Financial Information) (Details) - Enterprise Offshore Acquisition - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2016	Sep. 30, 2016
SelectedFinancialInformation [Line Items]
Revenues	$ 66,845	$ 181,227
Net income	$ 39,412	$ 103,249

[Line Items] for Selected Financial Information [Table Text Block]

No definition available.

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- Definition

This element represents the amount of earnings or loss of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)
-URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1392-128463

+ Details

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- Definition

This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

+ Details

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- Details

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