Note 1 - Description of Business	12 Months Ended
Dec. 31, 2022
Notes to Financial Statements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	1. DESCRIPTION OF BUSINESS AmerInst Insurance Group, Ltd., (“AmerInst,” “Company,” “we,” “our” or “us.”) was formed under the laws of Bermuda in 1998. The Company, through its wholly owned subsidiary AmerInst Insurance Company, Ltd. (“AMIC Ltd.”) and its predecessor AmerInst Insurance Company, Inc. (“AIIC Inc.”), were engaged in the reinsurance of claims-made insurance policies of participants in an American Institute of Certified Public Accountants (“AICPA”) sponsored insurance program that provided accountants’ professional liability insurance coverage (“AICPA Plan”) through December 31, 2008. Effective December 30, 2020, AMIC Ltd. merged with its wholly owned subsidiary, AmerInst Investment Company, Ltd., with AMIC Ltd. being the surviving entity. *Agency Agreements with C&F and ISMIE* On September 25, 2009, Protexure Insurance Agency, Inc. (“Protexure”), a subsidiary of AmerInst, entered into an agency agreement (the “C&F Agency Agreement”) with The North River Insurance Company, United States Fire Insurance Company, Crum & Forster Indemnity Company, Crum and Forster Insurance Company, and Crum & Forster Specialty Insurance Company (collectively, “C&F”) pursuant to which C&F appointed Protexure as its exclusive agent for the purposes of soliciting, underwriting, quoting, binding, issuing, cancelling, non-renewing and endorsing accountants’ professional liability and lawyers’ professional liability insurance coverage in all 50 states of the United States and the District of Columbia. In 2021, C&F and Protexure signed an addendum to the C&F Agency Agreement which terminated the C&F Agency Agreement effective March 31, 2022. Under the terms of the addendum, Protexure was permitted to issue new and renewal professional liability policies on behalf of C&F with effective dates no later than March 31, 2022. Effective January 1, 2022, Protexure entered into a Managing General Agency Agreement (the “ISMIE Agency Agreement”) with Amwins Specialty Casualty Solutions, LLC for policies written by ISMIE Mutual Insurance Company (“ISMIE”). Protexure is transitioning the lawyers and accountants’ professional liability policies previously written with C&F to ISMIE. Certain policies are and will also be written by the Hanover Insurance Company. The C&F Agency Agreement and the ISMIE Agency Agreement are referred to herein as, collectively, the “Agency Agreements.” *Reinsurance Agreement* We previously conducted reinsurance business through AMIC Ltd., our subsidiary, which was a registered insurer in Bermuda. On September 25, 2009, AMIC Ltd. entered into a professional liability quota share agreement with C&F (the “Reinsurance Agreement”) pursuant to which C&F agreed to cede, and AMIC Ltd. agreed to accept as reinsurance, a 50% quota share of C&F’s liability under insurance written by Protexure on behalf of C&F and classified by C&F as accountants’ professional liability and lawyers’ professional liability, subject to AMIC Ltd.’s surplus limitations. Policies written by insurers other than C&F were not subject to the 50% quota share reinsurance to AMIC Ltd. During the third quarter of 2021, C&F and AMIC Ltd. entered into a commutation agreement (the “C&F Commutation Agreement”), which became effective as of March 31, 2021, whereby C&F and AMIC Ltd. agreed to fully and finally settle and commute all their respective past, present and future obligations and liabilities, known and unknown, under the Reinsurance Agreement. In accordance with the C&F Commutation Agreement, in full satisfaction of AMIC Ltd.’s past, present and future obligations and liabilities under the Reinsurance Agreement, an aggregate sum of $26,076,000 was paid by AMIC Ltd. to C&F in October 2021. Following the commutation of all of AMIC’s reinsurance business and the decision by the Company’s board of directors not to resume reinsurance operations through AMIC, the Company made an application to the BMA to cancel AMIC’s insurance license. Effective May 17, 2022, AMIC Ltd.’s Class 3A insurance license was cancelled by the Bermuda Monetary Authority (BMA). *Historical Relationship with CAMICO* From June 1, 2005 through May 31, 2009, we were a party to a reinsurance contract with CAMICO Mutual Insurance Company (“CAMICO”), a California-based writer of accountants’ professional liability business. We decided not to renew the CAMICO contract and permitted the contract to expire pursuant to its terms on May 31, 2009. We remained potentially liable for claims related to coverage through May 31, 2009. During the first quarter of 2022, CAMICO and AMIC Ltd. entered into a commutation agreement (the “CAMICO Commutation Agreement”), which became effective December 31, 2021, whereby CAMICO and AMIC Ltd. agreed to fully and finally settle and commute all their respective past, present and future obligations and liabilities, known and unknown under the reinsurance contract between CAMICO and AMIC Ltd. In accordance with the CAMICO Commutation Agreement, in full satisfaction of AMIC Ltd.’s past present and future obligations and liabilities under the reinsurance contract between CAMICO and AMIC Ltd., an aggregate sum of $15,000 was paid by CAMICO to AMIC Ltd. in March 2022.

Note 1 - Description of Business

12 Months Ended

Dec. 31, 2022

Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]

1. DESCRIPTION OF BUSINESS

AmerInst Insurance Group, Ltd., (“AmerInst,” “Company,” “we,” “our” or “us.”) was formed under the laws of Bermuda in 1998. The Company, through its wholly owned subsidiary AmerInst Insurance Company, Ltd. (“AMIC Ltd.”) and its predecessor AmerInst Insurance Company, Inc. (“AIIC Inc.”), were engaged in the reinsurance of claims-made insurance policies of participants in an American Institute of Certified Public Accountants (“AICPA”) sponsored insurance program that provided accountants’ professional liability insurance coverage (“AICPA Plan”) through December 31, 2008. Effective December 30, 2020, AMIC Ltd. merged with its wholly owned subsidiary, AmerInst Investment Company, Ltd., with AMIC Ltd. being the surviving entity.

Agency Agreements with C&F and ISMIE

On September 25, 2009, Protexure Insurance Agency, Inc. (“Protexure”), a subsidiary of AmerInst, entered into an agency agreement (the “C&F Agency Agreement”) with The North River Insurance Company, United States Fire Insurance Company, Crum & Forster Indemnity Company, Crum and Forster Insurance Company, and Crum & Forster Specialty Insurance Company (collectively, “C&F”) pursuant to which C&F appointed Protexure as its exclusive agent for the purposes of soliciting, underwriting, quoting, binding, issuing, cancelling, non-renewing and endorsing accountants’ professional liability and lawyers’ professional liability insurance coverage in all 50 states of the United States and the District of Columbia.

In 2021, C&F and Protexure signed an addendum to the C&F Agency Agreement which terminated the C&F Agency Agreement effective March 31, 2022. Under the terms of the addendum, Protexure was permitted to issue new and renewal professional liability policies on behalf of C&F with effective dates no later than March 31, 2022.

Effective January 1, 2022, Protexure entered into a Managing General Agency Agreement (the “ISMIE Agency Agreement”) with Amwins Specialty Casualty Solutions, LLC for policies written by ISMIE Mutual Insurance Company (“ISMIE”). Protexure is transitioning the lawyers and accountants’ professional liability policies previously written with C&F to ISMIE. Certain policies are and will also be written by the Hanover Insurance Company. The C&F Agency Agreement and the ISMIE Agency Agreement are referred to herein as, collectively, the “Agency Agreements.”

Reinsurance Agreement

We previously conducted reinsurance business through AMIC Ltd., our subsidiary, which was a registered insurer in Bermuda. On September 25, 2009, AMIC Ltd. entered into a professional liability quota share agreement with C&F (the “Reinsurance Agreement”) pursuant to which C&F agreed to cede, and AMIC Ltd. agreed to accept as reinsurance, a 50% quota share of C&F’s liability under insurance written by Protexure on behalf of C&F and classified by C&F as accountants’ professional liability and lawyers’ professional liability, subject to AMIC Ltd.’s surplus limitations. Policies written by insurers other than C&F were not subject to the 50% quota share reinsurance to AMIC Ltd.

During the third quarter of 2021, C&F and AMIC Ltd. entered into a commutation agreement (the “C&F Commutation Agreement”), which became effective as of March 31, 2021, whereby C&F and AMIC Ltd. agreed to fully and finally settle and commute all their respective past, present and future obligations and liabilities, known and unknown, under the Reinsurance Agreement. In accordance with the C&F Commutation Agreement, in full satisfaction of AMIC Ltd.’s past, present and future obligations and liabilities under the Reinsurance Agreement, an aggregate sum of $26,076,000 was paid by AMIC Ltd. to C&F in October 2021. Following the commutation of all of AMIC’s reinsurance business and the decision by the Company’s board of directors not to resume reinsurance operations through AMIC, the Company made an application to the BMA to cancel AMIC’s insurance license. Effective May 17, 2022, AMIC Ltd.’s Class 3A insurance license was cancelled by the Bermuda Monetary Authority (BMA).

Historical Relationship with CAMICO

From June 1, 2005 through May 31, 2009, we were a party to a reinsurance contract with CAMICO Mutual Insurance Company (“CAMICO”), a California-based writer of accountants’ professional liability business. We decided not to renew the CAMICO contract and permitted the contract to expire pursuant to its terms on May 31, 2009. We remained potentially liable for claims related to coverage through May 31, 2009.

During the first quarter of 2022, CAMICO and AMIC Ltd. entered into a commutation agreement (the “CAMICO Commutation Agreement”), which became effective December 31, 2021, whereby CAMICO and AMIC Ltd. agreed to fully and finally settle and commute all their respective past, present and future obligations and liabilities, known and unknown under the reinsurance contract between CAMICO and AMIC Ltd. In accordance with the CAMICO Commutation Agreement, in full satisfaction of AMIC Ltd.’s past present and future obligations and liabilities under the reinsurance contract between CAMICO and AMIC Ltd., an aggregate sum of $15,000 was paid by CAMICO to AMIC Ltd. in March 2022.