Description of Business and Summary of Significant Accounting Policies - Description of Business (Details) - subsidiary	Dec. 31, 2017	Aug. 31, 2015
Business Acquisition [Line Items]
Number of owned subsidiaries	2
Kelway TopCo Limited
Business Acquisition [Line Items]
Percent of outstanding common stock purchased		65.00%
Non-controlling interest held		35.00%
Total percentage owned, after acquisition		100.00%

Number of Owned Subsidiaries

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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- Definition

Percentage of voting equity interests acquired in a business combination achieved in stages, including equity interests in the acquiree held by the acquirer immediately before the acquisition date and acquired at the acquisition date.

+ References

No definition available.

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- Definition

Percentage of equity in the acquiree held by the acquirer immediately before the acquisition date in a business combination.

+ References

No definition available.

+ Details

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