Supplemental Cash Flow Information - Changes in Non-Cash Working Capital Items Related to Operating Activities (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental Cash Flow Elements [Abstract]
Accounts receivable	$ (54,830)	$ 34,669	$ (24,285)
Prepaid expenses and other assets	(6,618)	5,983	804
Accounts payable and accrued liabilities	39,413	38,627	(23,745)
Advances from (to) affiliate	51,841	(5,061)	73,129
Change in non-cash working capital items related to operating activities	$ 29,806	$ 74,218	$ 25,903

The increase (decrease) during the reporting period in the amounts payable to vendors for goods and services received and the amount of obligations and expenses incurred but not paid.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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- Definition

The increase (decrease) during the reporting period in amount due within one year (or one business cycle) from customers for the credit sale of goods and services.

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- Definition

The increase (decrease) in obligations owed to an entity that is controlling, under the control of, or within the same control group as the reporting entity by means of direct or indirect ownership.

+ References

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- Definition

The increase (decrease) during the reporting period of all assets and liabilities used in operating activities.

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- Definition

Amount of increase (decrease) in prepaid expenses, and assets classified as other.

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- References

No definition available.

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