Accounting Policies - Segment Reporting and Accounts Receivable (Details)	12 Months Ended
Dec. 31, 2019 USD ($) segment customer	Dec. 31, 2018 USD ($) segment customer
Concentration Risk [Line Items]
Number of reportable segments \| segment	2	2
Allowance for doubtful accounts \| $	$ 0	$ 0
Accounts Receivable \| Customer Concentration Risk
Concentration Risk [Line Items]
Number of customers \| customer	1	2
Concentration risk, percentage	52.50%	50.40%

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
-Topic 275
-SubTopic 10
-Section 50
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration