Goodwill and Other Intangible Assets (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Line Items]
Goodwill, Amortization Period for Income Taxes	15 years
Glass Mountain Pipeline LLC [Member]
Goodwill [Line Items]
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 31,000
SemGas [Member]
Goodwill [Line Items]
Goodwill, Impairment Loss	$ 13,052
Crude Transportation [Member]
Goodwill [Line Items]
Goodwill, Impairment Loss		$ 9,488