Amount, after valuation allowance, recoverable under reinsurance contracts including premium paid under reinsurance contracts. Examples include, but are not limited to, settled and unsettled claims, incurred but not reported losses, loss adjustment expense, premium paid, policy benefits and policy reserves.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(6))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 20
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=99397103&loc=d3e6824-158387

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 310
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=99404803&loc=d3e21409-158489

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

Reinsurance and Catastrophes - Total Amounts of Reinsurance Recoverables On Unpaid Insurance Reserves (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary of reinsurance recoverable on unpaid insurance reserves
Reinsurance recoverables	$ 119.6	$ 122.5
Property & Casualty
Summary of reinsurance recoverable on unpaid insurance reserves
Reinsurance recoverables	110.3	112.9	$ 120.5	$ 89.7
Property & Casualty \| Reinsurance companies
Summary of reinsurance recoverable on unpaid insurance reserves
Reinsurance recoverables	10.4	13.2
Property & Casualty \| State insurance facilities
Summary of reinsurance recoverable on unpaid insurance reserves
Reinsurance recoverables	99.9	99.7
Life
Summary of reinsurance recoverable on unpaid insurance reserves
Reinsurance recoverables	$ 9.3	$ 9.6