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Investments - Additional Information (Detail) $ in Thousands | 12 Months Ended
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Dec. 31, 2015 USD ($) Securities | Dec. 31, 2014 USD ($) | Dec. 31, 2013 USD ($)
Investment [Line Items] |  |  |
Short-term investments | $ 7,718 | $ 33,684 |
Carrying value of investments | $ 12,200 |  |
Individual fixed maturity held in unrealized loss position | Securities | 198 |  |
Individual fixed maturity held in unrealized loss position longer than 12 months | Securities | 29 |  |
Number of fixed maturity securities to be deemed other-than-temporarily impaired | Securities | 4 |  |
Impairment losses recognized | $ 2,653 | 222 | $ 2,229
Held-to-Maturity Securities [Member] |  |  |
Investment [Line Items] |  |  |
Cash or cash held by insurance regulators | 20,300 |  |
Fixed Maturity Securities Available for Sale [Member] |  |  |
Investment [Line Items] |  |  |
Impairment losses recognized | 2,653 | 222 |
Cash [Member] |  |  |
Investment [Line Items] |  |  |
Cash or cash held by insurance regulators | 1,500 |  |
Corporate Bonds [Member] |  |  |
Investment [Line Items] |  |  |
Short-term investments | $ 7,700 | 32,700 |
Certificates of Deposit [Member] |  |  |
Investment [Line Items] |  |  |
Short-term investments |  | $ 1,000 |

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