Goodwill and Intangible Assets - Goodwill Roll Forward (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
Dec. 31, 2018	Jun. 30, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Beginning balance, January 1		$ 0	$ 69,483
Impairments	$ (69,500)	0	(69,483)
Ending balance	$ 0	$ 0	$ 0

Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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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
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-URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13777-109266

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