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Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions |  | 1 Months Ended | 6 Months Ended
--- | --- | --- | ---
Jul. 21, 2017 | Feb. 28, 2015 | Jun. 30, 2017
Loss Contingencies [Line Items] |  |  |
Retention amount |  |  | $ 5.0
AIIC [Member] | Iowa [Member] |  |  |
Loss Contingencies [Line Items] |  |  |
Appeal bond |  |  | 27.8
AIIC [Member] | 2009 Workers' Compensation Claim [Member] | Iowa [Member] |  |  |
Loss Contingencies [Line Items] |  |  |
Workers compensation claim, damages awarded |  | $ 25.3 |
Workers compensation claims contingency reserves |  |  | 2.4
Total amount expensed on workers compensation claim |  |  | $ 5.4
AIIC [Member] | Plaintiff Seeking Actual Damages [Member] | Iowa [Member] |  |  |
Loss Contingencies [Line Items] |  |  |
Amount of damages |  | 0.3 |
AIIC [Member] | Plaintiff Seeking Punitive Damages [Member] | Iowa [Member] |  |  |
Loss Contingencies [Line Items] |  |  |
Amount of damages |  | $ 25.0 |
Subsequent Event [Member] | AIIC [Member] |  |  |
Loss Contingencies [Line Items] |  |  |
Appeal bond returned amount | $ 27.8 |  |

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- Definition Appeal bond. + References No definition available. + Details
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- Definition Appeal bond returned due to court order. + References No definition available. + Details
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- Definition Workers compensation claims contingency reserves. + References No definition available. + Details
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- Definition Workers compensation claims contingency reserves plus inception to date loss and loss adjustment expense paid. + References No definition available. + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Amount of damages awarded to the plaintiff in the legal matter. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14435-108349 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14557-108349 + Details
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- Definition Stated amount that is the upper retention limit per entity policy. + References No definition available. + Details
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