Equity Method Investments - Summarized financial information - White Cliffs (Details) - White Cliffs Pipeline, L.L.C. [Member] - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Summarized income statement information
Equity Method Investment, Summarized Financial Information, Revenue	$ 41,962	$ 44,209	$ 87,586	$ 84,600
Equity Method Investment, Summarized Financial Information, Cost of Sales	(228)	(415)	(7)	(31)
Equity Method Investment, Summarized Financial Information, Operating, General and Administrative Expenses	8,047	6,594	16,859	11,997
Equity Method Investment, Summarized Financial Information, Depreciation and Amortization Expense	9,265	9,606	18,528	19,197
Equity Method Investment, Summarized Financial Information, Net Income (Loss)	$ 24,878	$ 28,423	$ 52,206	$ 53,437

Equity method investment, summarized financial information, depreciation and amortization expense.

No definition available.

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- Definition

Equity method investment, summarized financial information, operating, general and administrative expenses.

+ References

No definition available.

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- Definition

The amount of the cost of sales reported by an equity method investment of the entity.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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- References

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- Definition

The amount of net income (loss) reported by an equity method investment of the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount of revenue from sale of product and rendering of service reported by equity method investee.

+ References

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