Components of Working Capital - Other Current Assets Table (Details) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017
Other Current Assets [Line Items]
NGLs inventory		$ 6,370	$ 10,788
Imbalance receivables		8,864	1,640
Prepaid insurance		1,973	2,955
Contract assets		5,399	0
Other		4,184	0
Total other current assets	[1]	$ 26,790	$ 15,383

[1] Other current assets includes affiliate amounts of $3.7 million and zero as of December 31, 2018 and 2017, respectively.