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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Name:	us-gaap_GoodwillImpairmentLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Goodwill and Other Intangible Assets (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Line Items]
Goodwill, Amortization Period for Income Taxes	15 years
U.S. Liquids [Member]
Goodwill [Line Items]
Goodwill, Impairment Loss		$ 26,628
Impairment of Intangible Assets, Finite-lived		$ 12,087
U.S. Gas [Member]
Goodwill [Line Items]
Goodwill, Impairment Loss			$ 13,052