Summary of Significant Accounting Policies - Shipping Expense (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Shipping expenses	$ 0.5	$ 0.8	$ 1.4	$ 1.6

Cost incurred during the reporting period in transporting goods and services to customers. Includes freight-out costs.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84158767&loc=d3e18780-107790

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 45
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=68080631&loc=d3e61069-111654

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 45
-Section 45
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=68075638&loc=d3e60635-111653

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=84158767&loc=d3e18726-107790

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 45
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82851458&loc=d3e221937-122793

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