Investments in and Advances to Equity Accounted Joint Venture - Schedule of Investments in and Advances to Equity Accounted Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Investment in and advances to equity accounted investments	$ 26,351	$ 25,766
High-Q Joint Venture
Schedule of Equity Method Investments [Line Items]
Investment in and advances to equity accounted investments	$ 26,351	$ 25,766

Amount of investment in equity method investee and investment in and advance to affiliate.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant