Reinsurance - Additional Information (Detail) (USD $)	6 Months Ended			0 Months Ended	6 Months Ended
	Mar. 31, 2013	Oct. 17, 2011	Apr. 08, 2011	Jan. 01, 2013 Fgl Reinsurance Agreement With Fsr [Member]	Mar. 31, 2013 Nomura [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Fair value of insurance transferred assets		$ 580,700,000	$ 535,800,000
Pre-tax gain on reinsurance transactions deferred	18,000,000
Reserve financing facility					295,000,000
Upfront structuring fee					2,800,000
LetterofCreditFutureQuarterlyReductiun					6,300,000
Reinsurance arrangment in percentage				10.00%
Payments for reinsurance				$ 1,500,000,000