Major Customers - Narrative (Details) - Customer Concentration Risk - customer	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Sales Revenue, Services, Net
Concentration Risk [Line Items]
Concentration risk, number of customers	2	2
Sales Revenue, Services, Net \| Major Customer Number One
Concentration Risk [Line Items]
Concentration risk, percentage	25.00%	23.00%
Sales Revenue, Services, Net \| Major Customer Number Two
Concentration Risk [Line Items]
Concentration risk, percentage	21.00%	16.00%
Accounts Receivable \| Major Customer Number One
Concentration Risk [Line Items]
Concentration risk, percentage	54.00%
Accounts Receivable \| Major Customer Number Two
Concentration Risk [Line Items]
Concentration risk, percentage	1.00%

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
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13531-108611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13537-108611

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

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