Investment Securities - Summary of Net Investment Income (Loss) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Investment income (loss):
Amortization of premium or discount on fixed-maturity securities	$ (179)	$ (529)
Investment income on fixed-maturity securities	413	1,102
Interest income on cash and equivalents	57us-gaap_InvestmentIncomeInterest	2us-gaap_InvestmentIncomeInterest
Realized net gain (loss) from sale of investments	186us-gaap_GainLossOnSaleOfInvestments	27us-gaap_GainLossOnSaleOfInvestments
Unrealized (losses) gains on trading securities held at period end	(76)	66
Net investment income (loss)	$ 401us-gaap_InvestmentIncomeNet	$ 668us-gaap_InvestmentIncomeNet

The net realized gain (loss) on investments sold during the period, not including gains (losses) on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity, which, for cash flow reporting, is a component of proceeds from investing activities.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

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Amount before accretion (amortization) of purchase discount (premium) of interest income on nonoperating securities.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Article 5

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

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-Name Accounting Standards Codification

-Topic 225

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Amount after accretion (amortization) of discount (premium), and investment expense, of interest income and dividend income on nonoperating securities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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Amount of accretion (amortization) of purchase discount (premium) on nonoperating securities.

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Amount of unrealized holding gain (loss) recognized in the income statement for investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Trading Securities

-URI http://asc.fasb.org/extlink&oid=6526789

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Investment income on fixed-maturity securities.

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