Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified				6 Months Ended		1 Months Ended	6 Months Ended		6 Months Ended
	Mar. 31, 2014	Nov. 01, 2013	Apr. 06, 2011	Mar. 31, 2014 Maximum [Member]	Mar. 31, 2014 Minimum [Member]	Jul. 31, 2012 FGL [Member]	Mar. 31, 2014 FGL [Member]	Mar. 31, 2014 Spectrum Brands [Member]	Mar. 31, 2014 Cressy Plaintiff [Member]
Commitment And Contingencies [Line Items]
Loss Contingency, Receivable									$ 4.5
Reserves for legal, environmental and regulatory matters	24.2
Environmental costs recognized, capitalized								4.7
Accrued amount of guaranty fund assessments							4.8
Estimated future premium tax deductions							4.6
Pre-tax charge, net of reinsurance, to increase reserves to cover potential benefits payable						11.0
Administrative costs and potential liabilities							2.0
Estimated range of external legal costs				3.0	1.0
Notional amount of unfunded, legally binding lending commitments	207.4
Expiration of partial amount of unfunded, legally binding lending commitments	45.0
Expiry date of partial amount of notional amount				1 year
Expiry date of remainder part of notional amount				5 years	1 year
Statutory Accounting Practices, Change in Statutory Capital and Surplus Required as a Result of Electing New Statutory Accounting Practice		11.5
Statutory Accounting Practices, Statutory Capital and Surplus, Unassigned Balance Netted Against Additional Paid in Capital			805.8
Litigation Settlement, Amount									9.2
Estimated Litigation Liability									$ 7.1