Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Components of operating assets and liabilities
Increase (Decrease) in Restricted Cash	$ (33)	$ 1	$ 1
Decrease (increase) in accounts receivable	78,624	(237,394)	(90,810)
Decrease (increase) in receivable from affiliates	685	23,764	(19,541)
Decrease (increase) in inventories	52,166	(17,862)	(30,686)
Decrease (increase) in other current assets	(3,406)	2,947	634
Increase (decrease) in other noncurrent assets	1,636	14,307	297
Increase (decrease) in accounts payable and accrued liabilities	(78,829)	209,982	94,687
Increase (decrease) in payable to affiliates	(3,198)	(19,537)	21,475
Increase (decrease) in other noncurrent liabilities	1,374	19,385	2,573
Total changes in operating assets and liabilities	$ 45,813	$ (33,023)	$ (21,966)