Income Taxes - Unrecognized Tax Benefits - General Information (Details) $ in Millions	3 Months Ended	9 Months Ended
Jun. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense [Abstract]
Interest related to unrecognized benefits	$ 0.3	$ 0.9
Anticipated unrecognized tax benefit reduction during next twelve months	$ 1.9	$ 1.9

Amount of decrease reasonably possible in the next twelve months for the unrecognized tax benefit.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (d)(3)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319

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