Valuation and Qualifying Accounts (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Allowance for uncollectible reinsurance recoverables
Valuation and Qualifying Accounts Disclosure [Line Items]
Charged to Other Accounts
Allowance for Uncollectible Premiums Receivable
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	0.4	1.4	1.1
Charged to Costs and Expenses	0.6	(0.3)	1.1
Charged to Other Accounts
Deductions	0.5	0.7	0.8
Ending Balance	$ 0.5	$ 0.4	$ 1.4

Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 09

-Article 12

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Total of the deductions in a given period to allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, representing receivables written off as uncollectible and portions of the reserves utilized, respectively.

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