Value of Business Acquired and Changes in the Balances (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Acquisition [Line Items]
Balance, beginning of year	$ 0us-gaap_ValueOfBusinessAcquiredVOBA	$ 0us-gaap_ValueOfBusinessAcquiredVOBA	$ 0us-gaap_ValueOfBusinessAcquiredVOBA
Interest	314	439	573
Amortization	(3,479)	(4,327)	(5,218)
Change in shadow VOBA	3,165	3,888	4,645
Balance, end of year	$ 0us-gaap_ValueOfBusinessAcquiredVOBA	$ 0us-gaap_ValueOfBusinessAcquiredVOBA	$ 0us-gaap_ValueOfBusinessAcquiredVOBA

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Amount of adjustment to reflect the effect that would have been recognized had the unrealized holding gain (loss) actually been realized on the present value of future insurance profits being amortized using the gross profit method and the present value of future profits recognized as a result of a purchase of an insurance entity holding long-duration contracts.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

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- Definition

Amount of the present value of future profits asset amortized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 20

-Section S99

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- Definition

Amount of interest earned on present value of future insurance profits.

+ References

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- Definition

The remaining unamortized carrying amount as of the balance sheet date of expected future earnings from insurance contracts acquired (also known as present value of future profits).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

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-Section S99

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