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Related Party (Narrative) (Details) - Corporate Joint Venture - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2016
Related Party Transaction [Line Items]
Purchases from joint venture	$ 1,000
N-G, LLC
Related Party Transaction [Line Items]
Percent ownership		50.00%
Genis Holdings, LLC | N-G, LLC
Related Party Transaction [Line Items]
Percent ownership		50.00%
Prepaid Purchases From Joint Venture
Related Party Transaction [Line Items]
Amount prepaid on purchases from joint venture	$ 500

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- Definition

Percentage investment held by members or limited partners of limited liability company (LLC) or limited partnership (LP).

+ References

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- Definition

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