Goodwill and Other Intangible Assets (Details 1) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 34,230	$ 48,032
Currency translation adjustments	206	(750)
Goodwill, Ending Balance	257,302	34,230
U.S. Gas [Member]
Goodwill [Line Items]
Goodwill, Impairment Loss		$ 13,052
U.S. Liquids [Member]
Goodwill [Line Items]
Goodwill, Impairment Loss	26,628
HFOTCO LLC [Member] \| U.S. Liquids [Member]
Goodwill [Line Items]
Goodwill, Acquired During Period	257,302
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] \| Sem Mexico [Member]
Goodwill [Line Items]
Goodwill, Reclassification to Held-for-sale	$ 7,808

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- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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- Definition

Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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