Third Party Reinsurance (Sirius Group) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Reinsurance Retention Policy [Line Items]
Reinsurance recoverable on paid losses	$ 15.2	$ 25.4
Reinsurance recoverable on unpaid losses	425.2	428.1
Sirius
Reinsurance Retention Policy [Line Items]
Reinsurance recoverable on paid losses	12.2	15.7
Reinsurance recoverable on unpaid losses	$ 344.8	$ 347.9

Amount after valuation allowance of reinsurance recoverables for losses reported to the ceding insurer but not yet paid, amounts expected of incurred losses and settlement expenses, which have not yet been reported to the ceding insurer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 310

-Section 45

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6485522&loc=d3e21412-158489

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