Basis of Presentation	9 Months Ended
Dec. 31, 2020
Disclosure Text Block [Abstract]
1. Basis of Presentation	1.Basis of Presentation AMERCO, a Nevada corporation (“AMERCO”), has a third fiscal quarter that ends on the 31st of December for each year that is referenced. Our insurance company subsidiaries have a third quarter that ends on the 30 th of September for each year that is referenced. They have been consolidated on that basis. Our insurance companies' financial reporting processes conform to calendar year reporting as required by state insurance departments. Management believes that consolidating their calendar year into our fiscal year financial statements does not materially affect the presentation of financial position or results of operations. We disclose material events, if any, occurring during the intervening period. Consequently, all references to our insurance subsidiaries' years 2020 and 2019 correspond to fiscal 2021 and 2020 for AMERCO. Accounts denominated in non-U.S. currencies have been translated into U.S. dollars. The condensed consolidated balance sheet as of December 31, 2020 and the related condensed consolidated statements of operations, comprehensive income (loss), stockholders' equity for the third quarter and first nine months of fiscal 2021 and 2020 and cash flows for the first nine months of fiscal 2021 and 2020 are unaudited. In our opinion, all adjustments necessary for the fair presentation of such condensed consolidated financial statements have been included. Such adjustments consist only of normal recurring items. Interim results are not necessarily indicative of results for a full year. The information in this Quarterly Report on Form 10-Q (“Quarterly Report”) should be read in conjunction with Management's Discussion and Analysis of Financial Condition and Results of Operations and financial statements and notes thereto included in our Annual Report on Form 10-K for the fiscal year ended March 31, 2020. Intercompany accounts and transactions have been eliminated. Description of Legal Entities AMERCO is the holding company for: U-Haul International, Inc. (“U-Haul”); Amerco Real Estate Company (“Real Estate”); Repwest Insurance Company (“Repwest”); and Oxford Life Insurance Company (“Oxford”). Unless the context otherwise requires, the terms “Company,” “we,” “us” or “our” refer to AMERCO and all of its legal subsidiaries. Description of Operating Segments AMERCO has three ( 3 ) reportable segments. They are Moving and Storage, Property and Casualty Insurance and Life Insurance. The Moving and Storage operating segment (“Moving and Storage”) includes AMERCO, U-Haul and Real Estate and the wholly owned subsidiaries of U-Haul and Real Estate. Operations consist of the rental of trucks and trailers, sales of moving supplies, sales of towing accessories, sales of propane, and the rental of fixed and portable moving and storage units to the “do-it-yourself” mover and management of self-storage properties owned by others. Operations are conducted under the registered trade name U-Haul ® throughout the United States and Canada. The Property and Casualty Insurance operating segment (“Property and Casualty Insurance”) includes Repwest and its wholly owned subsidiaries and ARCOA Risk Retention Group (“ARCOA”). Property and Casualty Insurance provides loss adjusting and claims handling for U-Haul ® through regional offices in the United States and Canada. Property and Casualty Insurance also underwrites components of the Safemove ® , Safetow ® , Safemove Plus ® , Safestor ® and Safestor Mobile ® protection packages to U-Haul customers. The business plan for Property and Casualty Insurance includes offering property and casualty insurance products in other U-Haul-related programs. ARCOA is a group captive insurer owned by us and our wholly owned subsidiaries whose purpose is to provide insurance products related to our moving and storage business. 8 amerco and consolidated subsidiaries notes to condensed consolidated financial statements - (continued) The Life Insurance operating segment (“Life Insurance”) includes Oxford and its wholly owned subsidiaries. Life Insurance provides life and health insurance products primarily to the senior market through the direct writing and reinsuring of life insurance, Medicare supplement and annuity policies. Summary of Significant Accounting Polices Refer to our Annual Report on Form 10-K for the fiscal year ended March 31, 2020 for a summary of significant accounting policies. At the beginning of the first quarter of fiscal 2021, we adopted Accounting Standards Update 2016-13 , Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). ASU 2016-13 replaces the incurred loss impairment methodology with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. In addition, new disclosures are required. The new standard requires that expected credit losses relating to financial assets measured on an amortized cost basis and available-for-sale debt securities be recorded through an allowance for credit losses. It also limits the amount of credit losses to be recognized for available-for-sale debt securities to the amount by which carrying value exceeds fair value and also requires the reversal of previously recognized credit losses if fair value increases. We adopted ASU 2016-13 using the modified retrospective method for all financial assets measured at amortized cost. We modified our policy on accounting for allowance for doubtful accounts on trade accounts receivable. We perform ongoing credit evaluations of our customers and assess each customer's credit worthiness. We monitor collections and payments from our customers and maintain an allowance for doubtful accounts based upon applying an expected credit loss rate to receivables based on the historical loss rate from similar high risk customers adjusted for current conditions, including any specific customer collection issues identified, and forecasts of economic conditions. Delinquent account balances are written off after management has determined that the likelihood of collection is remote. The adoption of ASU 2016-13 resulted in a cumulative-effect adjustment to the opening balance of retained earnings of $2.9 million and did not have a material impact on our results of operations, financial condition or liquidity. Please see Note 16, Allowance for Credit Losses, of the Notes to Condensed Consolidated Financial Statements.

Basis of Presentation

9 Months Ended

Dec. 31, 2020

1.Basis of Presentation AMERCO, a Nevada corporation (“AMERCO”), has a third fiscal quarter that ends on the 31st of December for each year that is referenced. Our insurance company subsidiaries have a third quarter that ends on the 30 th of September for each year that is referenced. They have been consolidated on that basis. Our insurance companies' financial reporting processes conform to calendar year reporting as required by state insurance departments. Management believes that consolidating their calendar year into our fiscal year financial statements does not materially affect the presentation of financial position or results of operations. We disclose material events, if any, occurring during the intervening period. Consequently, all references to our insurance subsidiaries' years 2020 and 2019 correspond to fiscal 2021 and 2020 for AMERCO. Accounts denominated in non-U.S. currencies have been translated into U.S. dollars. The condensed consolidated balance sheet as of December 31, 2020 and the related condensed consolidated statements of operations, comprehensive income (loss), stockholders' equity for the third quarter and first nine months of fiscal 2021 and 2020 and cash flows for the first nine months of fiscal 2021 and 2020 are unaudited. In our opinion, all adjustments necessary for the fair presentation of such condensed consolidated financial statements have been included. Such adjustments consist only of normal recurring items. Interim results are not necessarily indicative of results for a full year. The information in this Quarterly Report on Form 10-Q (“Quarterly Report”) should be read in conjunction with Management's Discussion and Analysis of Financial Condition and Results of Operations and financial statements and notes thereto included in our Annual Report on Form 10-K for the fiscal year ended March 31, 2020. Intercompany accounts and transactions have been eliminated. Description of Legal Entities AMERCO is the holding company for: U-Haul International, Inc. (“U-Haul”); Amerco Real Estate Company (“Real Estate”); Repwest Insurance Company (“Repwest”); and Oxford Life Insurance Company (“Oxford”). Unless the context otherwise requires, the terms “Company,” “we,” “us” or “our” refer to AMERCO and all of its legal subsidiaries. Description of Operating Segments AMERCO has three ( 3 ) reportable segments. They are Moving and Storage, Property and Casualty Insurance and Life Insurance. The Moving and Storage operating segment (“Moving and Storage”) includes AMERCO, U-Haul and Real Estate and the wholly owned subsidiaries of U-Haul and Real Estate. Operations consist of the rental of trucks and trailers, sales of moving supplies, sales of towing accessories, sales of propane, and the rental of fixed and portable moving and storage units to the “do-it-yourself” mover and management of self-storage properties owned by others. Operations are conducted under the registered trade name U-Haul ® throughout the United States and Canada. The Property and Casualty Insurance operating segment (“Property and Casualty Insurance”) includes Repwest and its wholly owned subsidiaries and ARCOA Risk Retention Group (“ARCOA”). Property and Casualty Insurance provides loss adjusting and claims handling for U-Haul ® through regional offices in the United States and Canada. Property and Casualty Insurance also underwrites components of the Safemove ® , Safetow ® , Safemove Plus ® , Safestor ® and Safestor Mobile ® protection packages to U-Haul customers. The business plan for Property and Casualty Insurance includes offering property and casualty insurance products in other U-Haul-related programs. ARCOA is a group captive insurer owned by us and our wholly owned subsidiaries whose purpose is to provide insurance products related to our moving and storage business. 8 amerco and consolidated subsidiaries notes to condensed consolidated financial statements - (continued) The Life Insurance operating segment (“Life Insurance”) includes Oxford and its wholly owned subsidiaries. Life Insurance provides life and health insurance products primarily to the senior market through the direct writing and reinsuring of life insurance, Medicare supplement and annuity policies. Summary of Significant Accounting Polices Refer to our Annual Report on Form 10-K for the fiscal year ended March 31, 2020 for a summary of significant accounting policies. At the beginning of the first quarter of fiscal 2021, we adopted Accounting Standards Update 2016-13 , Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). ASU 2016-13 replaces the incurred loss impairment methodology with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. In addition, new disclosures are required. The new standard requires that expected credit losses relating to financial assets measured on an amortized cost basis and available-for-sale debt securities be recorded through an allowance for credit losses. It also limits the amount of credit losses to be recognized for available-for-sale debt securities to the amount by which carrying value exceeds fair value and also requires the reversal of previously recognized credit losses if fair value increases. We adopted ASU 2016-13 using the modified retrospective method for all financial assets measured at amortized cost. We modified our policy on accounting for allowance for doubtful accounts on trade accounts receivable. We perform ongoing credit evaluations of our customers and assess each customer's credit worthiness. We monitor collections and payments from our customers and maintain an allowance for doubtful accounts based upon applying an expected credit loss rate to receivables based on the historical loss rate from similar high risk customers adjusted for current conditions, including any specific customer collection issues identified, and forecasts of economic conditions. Delinquent account balances are written off after management has determined that the likelihood of collection is remote. The adoption of ASU 2016-13 resulted in a cumulative-effect adjustment to the opening balance of retained earnings of $2.9 million and did not have a material impact on our results of operations, financial condition or liquidity. Please see Note 16, Allowance for Credit Losses, of the Notes to Condensed Consolidated Financial Statements.