Related Party Transactions (Related Party Assets) (Details) Parenthetical $ in Millions	9 Months Ended
Dec. 31, 2020 USD ($)
Oxford
Related Party Transaction, Due from (to) Related Party [Abstract]
Paid dividend, related party	$ 22.6
Repwest
Related Party Transaction, Due from (to) Related Party [Abstract]
Notes receivable, related party	$ 12.0

Financial instruments issued by insurance entities (surplus notes) that are includable in surplus for statutory accounting purposes as prescribed or permitted by state laws and regulations that are liabilities of the issuer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 470
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6486086&loc=d3e24387-158525

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