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Subordinated Debt Securities - Additional Information (Detail) (USD $) | 0 Months Ended | 1 Months Ended | 12 Months Ended |  | 0 Months Ended | 12 Months Ended | 0 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | --- | --- | --- | ---
Apr. 29, 2004 | Dec. 16, 2003 | Aug. 31, 2012 | May 31, 2012 | Jul. 31, 2011 | Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2013 | Dec. 16, 2003 Amerisafe Capital Trust I [Member] | Dec. 31, 2013 Amerisafe Capital Trust I [Member] | Apr. 29, 2004 Amerisafe Capital Trust II [Member] | Dec. 31, 2013 Amerisafe Capital Trust II [Member]
Subordinated Borrowing [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Purchase of subordinated debt securities | $ 25,800,000 | $ 10,300,000 |  |  |  |  |  |  |  |  |  |  |
Preferred securities to investors | 25,000,000 | 10,000,000 |  |  |  |  |  |  |  | 10,000,000 |  | 25,000,000 |
Common securities to the Company |  |  |  |  |  |  |  |  |  | 300,000 |  | 800,000 |
Redemption of debt securities |  |  | $ 12,900,000 | $ 12,900,000 | $ 10,300,000 | $ 25,780,000 | $ 10,310,000 |  |  |  |  |  |
Subordinated debt securities quarterly rate |  |  |  |  |  |  |  |  |  |  | LIBOR plus 4.10% |  | LIBOR plus 3.80% per annum
Debt securities interest rate | 3.80% | 4.10% |  |  |  |  | 4.30% | 4.40% |  |  |  |  |
Subordinated debt securities due |  |  |  |  |  |  |  |  | 2034 |  |  |  |

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- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
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- Definition The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR. + References No definition available. + Details
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- Definition The cash outflow to acquire equity securities classified as available-for-sale securities, because they are not classified as trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Investing Activities -URI http://asc.fasb.org/extlink&oid=6516133 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26853-111562 + Details
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- Definition The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt. + References No definition available. + Details
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- Definition The cash inflow from issuance of preferred stocks by a business trust or other special purpose entity, mainly established by a bank holding entity, to third party investors. The trust's assets are deeply subordinated debentures of the bank holding entity. Most trust preferred securities are subject to a mandatory redemption upon the repayment of the debentures. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Financing Activities -URI http://asc.fasb.org/extlink&oid=6513228 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3255-108585 + Details
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- Definition The cash outflow from the repayment of long-term borrowing where a lender is placed in a lien position behind debt having a higher priority of repayment (senior) in case of liquidation of the entity's assets or underlying collateral. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Financing Activities -URI http://asc.fasb.org/extlink&oid=6513228 + Details
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