Significant Accounting Policies (Policies)	12 Months Ended
Significant Accounting Policies (Policies)	Dec. 31, 2019
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of presentation The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and include the accounts of AmerInst and its operating wholly owned subsidiaries, AmerInst Mezco, Ltd. (“Mezco”), AMIC Ltd., Protexure and AmerInst Investment Company, Ltd. (“Investco”). Intercompany accounts and transactions have been eliminated on consolidation. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The major estimates reflected in the Company’s financial statements include but are not limited to the liability for loss and loss adjustment expenses.
Premiums Receivable, Basis of Accounting, Policy [Policy Text Block]	Premiums Premiums assumed are earned on a pro rata basis over the terms of the underlying policies to which they relate. Premiums assumed relating to the unexpired portion of policies in force at the balance sheet date are recorded as unearned premiums.
Deferred Charges, Policy [Policy Text Block]	Deferred policy acquisition costs Ceding commissions related to assumed reinsurance agreements are deferred and amortized pro rata over the terms of the underlying policies to which they relate.
Liability Reserve Estimate, Policy [Policy Text Block]	Liability for losses and loss adjustment expenses The liability for unpaid losses and loss adjustment expenses includes case basis estimates of reported losses plus supplemental amounts for projected losses incurred but not reported (IBNR), calculated based upon loss projections utilizing certain actuarial assumptions and AMIC Ltd.’s historical loss experience supplemented with industry data. The aggregate liability for unpaid losses and loss adjustment expenses at year end represents management’s best estimate, based upon the available data, of the amount necessary to cover the ultimate cost of loss, based upon an actuarial analysis prepared by independent actuaries. However, because of the volatility inherent in professional liability coverage, actual loss experience may not conform to the assumptions used in determining the estimated amounts for such liability at the balance sheet date. Accordingly, the ultimate liability could be significantly in excess of or less than the amount indicated in the financial statements. As adjustments to these estimates become necessary, such adjustments are reflected in current operations. AMIC Ltd. does not discount its loss reserves for purposes of these financial statements. We review the independent actuaries’ reports for consistency and appropriateness of methodology and assumptions, including assumptions of industry benchmarks and discuss any concerns or changes with them. Our Underwriting Committee then considers the reasonableness of loss reserves recommended by our independent actuaries, in light of actual loss development during the year and approve the loss reserves to be recorded by AMIC Ltd. The anticipated effect of inflation is implicitly considered when estimating liabilities for unpaid losses and loss adjustment expenses. Future average severities are projected based on historical trends adjusted for anticipated trends, are monitored based on actual developments and are modified if necessary.
Investment, Policy [Policy Text Block]	Investments AmerInst classifies its fixed maturity investments as available-for-sale. Accordingly, AmerInst reports these fixed income securities at their estimated fair values with unrealized holding gains and losses being reported as other comprehensive income (loss). Realized gains and losses on sales of fixed maturity investments are accounted for by specifically identifying the cost and are reflected in the income statement in the period of sale. Declines in the fair value of fixed maturity investments below cost are evaluated for other than temporary impairment losses. The evaluation for other than temporary impairment losses is a quantitative and qualitative process which is subject to risks and uncertainties in the determination of whether declines in the fair value of fixed maturity investments are other than temporary. The risks and uncertainties include the Company’s intent and ability to hold the security, changes in general economic conditions, the issuer’s financial condition or near term recovery prospects, and the effects of changes in interest rates. AmerInst’s accounting policy requires that a decline in the value of a fixed maturity security below its cost basis be assessed to determine if the decline is other than temporary. If so, the fixed maturity security is deemed to be impaired and a charge is recorded in net realized losses equal to the difference between the fair value and the cost basis of the security. The fair value of the impaired investment becomes its new cost basis. AmerInst classifies its equity securities as available-for-sale. Our equity investments are carried at fair value and as a result of our adoption of ASU- 2016 - 01 on January 1, 2018, the changes in fair value of our equity investments subsequent to January 1, 2018 are recognized within net realized and unrealized gains (losses) on the consolidated statement of operations.
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and cash equivalents Cash equivalents include money market funds and highly liquid debt instruments purchased with an original maturity of three months or less. Cash and cash equivalents are recorded at amortized cost, which approximates fair value due to the short-term, liquid nature of these securities.
Property, Plant and Equipment, Policy [Policy Text Block]	Property and Equipment Property and equipment are depreciated using the straight-line method with estimated useful lives ranging from 3 to 7 years. Expenditures for major renewals and betterments that extend the useful lives of property and equipment are capitalized. Expenditures for normal maintenance and repairs are expensed as incurred. Developmental costs for internal use software are capitalized in accordance with the provisions of the Financial Accounting Standard Board (“FASB”) Accounting Standards Codification (“ASC”) topic 350 “Intangibles—Goodwill and Other”, generally, when the preliminary project stage is completed, management commits to funding and it is probable that the project will be completed and the software will be used to perform the functions intended. Capitalized internal use software costs are amortized on a straight-line basis over their estimated useful lives, generally for a period not to exceed 5 years.
Income Tax, Policy [Policy Text Block]	Income taxes Deferred tax assets and liabilities are recognized for the future tax consequences and benefits attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the periods in which those temporary differences are expected to be recovered or settled. A valuation allowance is provided if it is more likely than not that some or all of the deferred tax assets will not be realized. Management evaluates the reliability of the deferred tax assets and assesses the need for additional valuation allowance annually.
Earnings Per Share, Policy [Policy Text Block]	Earnings per common share Basic earnings per share is determined as net income available to common shareholders divided by the weighted average number of common shares outstanding for the period. Diluted earnings per share reflect the impact of the Company’s stock option plan.
New Accounting Pronouncements, Policy [Policy Text Block]	New Accounting Pronouncements New Accounting Standards Adopted in 201 9 Leases In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016 - 02, which is codified in Accounting Standards Codification (“ASC”) 842, amending the guidance on the classification, measurement and disclosure of leases for both lessors and lessees. The ASU requires lessees to recognize a right-of-use asset and an offsetting lease liability on the balance sheet and to disclose qualitative and quantitative information about leasing arrangements. Subsequently, in July 2018, the FASB issued ASU 2018 - 10, which clarifies how to apply certain aspects of ASC 842. The amendments in the ASU address a number of issues in the new leases guidance, including ( 1 ) the rate implicit in the lease, ( 2 ) impairment of the net investment in the lease, ( 3 ) lessee reassessment of lease classification, ( 4 ) lessor reassessment of lease term and purchase options, ( 5 ) variable payments that depend on an index or rate, and ( 6 ) certain transition adjustments. In July 2018, the FASB also issued ASU 2018 - 11, which adds a transition option for all entities and a practical expedient only for lessors to ASU 2016 - 02. The transition option, which we elected on adoption of the guidance, allows entities to choose not to apply the new leases standard in the comparative periods they present in their financial statements in the year of adoption. Under the transition option, entities can instead opt to continue to apply the legacy guidance in ASC 840—Leases, including its disclosure requirements, in the comparative periods presented in the year they adopt the new leases standard. This means that entities that elect this option will only provide annual disclosures for the comparative periods because ASC 840 does not require interim disclosures. Entities that elect this transition option will still be required to adopt the new leases standard using the modified retrospective transition method required by the standard, but they will recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption rather than in the earliest period presented. The practical expedient provides lessors with an option to not separate the non-lease components from the associated lease components when certain criteria are met and requires them to account for the combined component in accordance with the revenue recognition standard in ASC 606 if the associated non-lease components are the predominant components. The Company adopted the new leasing standard and the related amendments on January 1, 2019. The Company believes the most significant change relates to the recognition of new right of use assets and lease liabilities on the consolidated balance sheet for Protexure’s real estate operating lease. These assets and liabilities, which are included in the “Prepaid expenses and other assets“ line and “Accrued expenses and other liabilities” line of the Condensed Consolidated Balance Sheets, respectively, represent less than 1% of the Company’s total assets and total liabilities. The adoption did not have a material impact on its consolidated financial statements. Changes to the Disclosure Requirements for Fair Value Measurements In August 2018, the FASB issued ASU 2018 - 13, which amended the fair value measurement guidance in ASC 820—Fair Value Measurement, by removing and modifying certain existing disclosure requirements, while also adding new disclosure requirements. . We adopted the new standard as of December 31, 2019 however these new or modified disclosures did not have a material impact on the fair value measurement disclosures included in our consolidated financial statements. Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income In February 2018, the FASB issued ASU 2018 - 02, which gives entities the option to reclassify to retained earnings tax effects related to items in accumulated other comprehensive income (“AOCI”) that are deemed stranded in AOCI as a result of the Tax Cuts and Jobs Act (the "Tax Act") enacted in the United States at the end of 2017. The amendments in this guidance eliminate the stranded tax effects resulting from the Tax Act and will improve the usefulness of information reported to financial statement users. We adopted the new standard on January 1, 2019 and that adoption did not have a material impact on our consolidated financial statements and related disclosures. Premium Amortization on Purchased Callable Debt Securities Effective January 1, 2019, the Company adopted ASU 2017 - 08, "Receivables - Nonrefundable Fees and Other Costs (Subtopic 310 - 20 ) - Premium Amortization on Purchased Callable Debt Securities," which shortens the amortization period for certain purchased callable debt securities held at a premium. The adoption of this guidance did not materially impact the Company's results of operations, financial condition or liquidity. Accounting Standards Not Yet Adopted Financial Instruments Credit Losses-Measurement of Credit Losses on Financial Instruments In June 2016, the FASB issued ASU 2016 - 13, which amends the guidance on impairment of financial instruments and significantly changes how entities will measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. The ASU will replace the existing “incurred loss” approach, with an “expected loss” model for instruments measured at amortized cost and require entities to record allowances for available-for-sale debt securities rather than reduce the carrying amount under the existing other-than temporary-impairment model. The ASU also simplifies the accounting model for purchased credit-impaired debt securities and loans. The Company's insurance premium balances receivable are also more significant financial assets within the scope of ASU 2016 - 13. The guidance requires financial assets to be presented at the net amount expected to be collected. The tentative effective date for the ASU is January 1, 2023. We do not expect the adoption of this ASU to have a material impact on our consolidated financial statements.