Concentrations of Credit Risk (Details) - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Concentration Risk
Adjustments to the fair value of derivative contracts due to credit related concerns outside of the normal non-performance risk adjustment	$ 0
Accounts receivable \| Customer concentration
Concentration Risk
Concentration risk	64.00%	59.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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