Statutory Information and Dividend Restrictions - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Insurance [Abstract]
Minimum statutory-basis capital and surplus	$ 113.2	$ 108.1
Restricted net assets of HMEC's insurance subsidiaries	26.9	$ 26.0
Aggregate amount of dividends	$ 248.7

Amount of statutory capital required to be maintained as of the balance sheet date under prescribed or permitted statutory accounting practices.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6486098&loc=d3e24708-158529

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