Summary of Significant Accounting Policies - Accounts Receivable (Details) $ in Millions	Sep. 30, 2021 USD ($)
Accounts Receivable
Allowance for uncollectible accounts	$ 0.0
Unbilled accounts receivable	$ 2.0

Allowance for uncollectible accounts.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 978
-SubTopic 310
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=68077313&loc=d3e27327-108691

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 978
-SubTopic 310
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=68077313&loc=d3e27327-108691

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