Income Taxes - Unrecognized Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
Jun. 30, 2018	Sep. 30, 2018
Income Taxes
Unrecognized tax benefits	$ 2,500	$ 2,500
Unrecognized tax benefits that if recognized, would impact the tax expense and effective tax rate	2,300
Unrecognized tax benefits cumulative interest and penalties recorded	$ 0	$ 0

Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319

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