Insurance Subsidiaries (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Parent Company And Unregulated Subsidiaries
Cash and Cash Equivalents [Line Items]
Investments and cash	$ 50.0	$ 156.0
Regulated Subsidiaries
Cash and Cash Equivalents [Line Items]
Investments and cash	$ 101.1	$ 107.3

Sum of investments and unrestricted cash as of the balance sheet date.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1,2)
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

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