Reinsurance (Effect Of Reinsurance On Certain Assets And Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Reinsurance Disclosures [Abstract]
Policy liabilities, assumed	$ 47.2	$ 56.7
Unearned income, assumed	0.6	0.5
Premiums payable, ceded	5.2	9.3
Premiums receivable, assumed	$ 25.9	$ 23.2

Liability as of the balance sheet date for the estimated ultimate cost of settling claims and claim adjustment expense relating to insured events that have occurred on or before the balance sheet date for those liabilities owed to another party as a result of assuming another insurer's primary obligation.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6482485&loc=d3e14764-158437

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