Borrowings	12 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Borrowings	Note 8.   Borrowings Long-Term Debt Long-term debt was as follows:                       March 31,   2022 Rates   Maturities   2022   2021                     (In thousands) Real estate loan (amortizing term)       1.83 %     2023 $ 50,259 $ 82,913 Senior mortgages 2.70 % - 5.50 % 2023 - 2042   2,206,268   2,125,324 Real estate loans (revolving credit) (a) 1.58 % - 3.14 % 2023 - 2025   535,000   535,000 Fleet loans (amortizing term) 1.61 % - 4.66 % 2022 - 2028   124,651   176,295 Fleet loans (revolving credit) 1.30 % - 2.36 % 2024 - 2026   560,000   535,000 Finance leases (rental equipment) 2.16 % - 5.04 % 2022 - 2026   347,393   513,623 Finance liability (rental equipment) 1.60 % - 4.68 % 2024 - 2030   949,936   644,375 Private placements 2.43 % - 2.88 % 2029 - 2035   1,200,000   – Other obligations 1.50 % - 8.00 % 2022 - 2049   86,206   86,085 Notes, loans and finance leases payable                 $ 6,059,713 $ 4,698,615 Less: Debt issuance costs                   (37,216)   (29,708) Total notes, loans and finance leases payable, net         $ 6,022,497 $ 4,668,907                           (a) Certain loans have interest rate swaps fixing the rate between 3.03% and 3.14% based on current margin         Real Estate Backed Loans Real Estate Loan Real Estate and certain of its subsidiaries and U-Haul Company of Florida are borrowers under a real estate loan (the “Real Estate Loan”).   The Real Estate Loan requires monthly principal and interest payments, with the unpaid loan balance and accrued and unpaid interest due at maturity. The Real Estate Loan is secured by various properties owned by the borrowers.   The interest rate, per the provisions of the amended loan agreement, is the applicable LIBOR plus the applicable margin. As of March 31, 2022, the applicable LIBOR was 0.33 % and the applicable margin was 1.50 %, the sum of which was 1.83 %. The default provisions of the Real Estate Loan include non-payment of principal or interest and other standard reporting and change-in-control covenants. There are limited restrictions regarding our use of the funds. Senior Mortgages Various subsidiaries of Real Estate and U-Haul are borrowers under certain senior mortgages. The senior mortgages require monthly principal and interest payments. The senior mortgages are secured by certain properties owned by the borrowers. The fixed interest rates, per the provisions of the senior mortgages, range between 2.70% and 5.50%. The weighted average interest rate of these loans as of March 31, 2022 was 4.0%.  Certain senior mortgages have an anticipated repayment date and a maturity date. If these senior mortgages are not repaid by the anticipated repayment date, the interest rate on these mortgages would increase from the current fixed rate. We are using the anticipated repayment date for our maturity schedule. Real Estate and U-Haul have provided limited guarantees of the senior mortgages. The default provisions of the senior mortgages include non-payment of principal or interest and other standard reporting and change-in-control covenants. There are limited restrictions regarding our use of the funds. Real Estate Loans (Revolving Credit) Various subsidiaries of Real Estate are borrowers under asset-backed real estate loans with an aggregate borrowing capacity of $ 385.0 million. As of March 31, 2022, the outstanding balance of these loans in the aggregate was $ 385.0 million. These loans are secured by certain properties owned by the borrowers. The loan agreements provide for term loans, subject to the terms of the loan agreements. The loans require monthly interest payments with the unpaid loan balance and accrued and unpaid interest due at maturity. The interest rate, per the provision of the loan agreements, is the applicable LIBOR plus the applicable margin. As of March 31, 2022, the applicable LIBOR was between 0.21 % and 0.45 % and the margin was between 1.25 % and 1.50 %, the sum of which was between 1.46 % and 1.85 %. AMERCO is the guarantor of these loans. The default provisions of the loan include non-payment of principal or interest and other standard reporting and change-in-control covenants. These loan agreements contain fallback language for the replacement of LIBOR. AMERCO is a borrower under a real estate loan. The current maximum credit commitment is $ 200.0 million, which can be increased to $ 300.0 million by bringing in other lenders. As of March 31, 2022, the outstanding balance was $ 150.0 million. This loan agreement provides for revolving loans, subject to the terms of the loan agreement. This loan requires monthly interest payments with the unpaid loan balance and accrued and unpaid interest due at maturity. As of March 31, 2022, the applicable LIBOR was 0.21 % and the margin was 1.38 %, the sum of which was 1.59 %. The default provisions of the loan include non-payment of principal or interest and other standard reporting and change-in-control covenants. There is a 0.30 % fee charged for unused capacity. This loan agreement contains fallback language for the replacement of LIBOR. Fleet Loans Rental Truck Amortizing Loans The amortizing loans require monthly principal and interest payments, with the unpaid loan balance and accrued and unpaid interest due at maturity. These loans were used to purchase new trucks. The interest rates, per the provision of the loan agreements, are carried at fixed rates ranging between 1.61 % and 4.66 %.   All of our rental truck amortizing loans are collateralized by the rental equipment purchased.   The majority of these loans are funded at 70%, but some may be funded at 100%. AMERCO, and in some cases U-Haul, is guarantor of these loans. The default provisions of these loans include non-payment of principal or interest and other standard reporting and change-in-control covenants. Rental Truck Revolvers Various subsidiaries of U-Haul entered into three revolving fleet loans with an aggregate borrowing capacity of $ 590.0 million. The outstanding balance for these revolvers is $ 560.0 million. The interest rates, per the provision of the loan agreements, in aggregate of $ 385.0 million, are the applicable LIBOR plus the applicable margin. As of March 31, 2022, the applicable LIBOR was 0.21 % and the margin was between 1.15 % and 1.25 %, the sum of which was between 1.36 % and 1.46 %. Of this $385.0 million outstanding, $ 100.0 million was fixed with an interest rate of 2.36 %.   The other loan of $175.0 million uses the Secured Overnight Funding Rate which interest rate was 0.05% plus a margin of 1.25% totaling 1.30% as of March 31, 2022.   Only interest is paid on the loans until the last nine months of the respective loan terms when principal becomes due monthly. These loan agreements either contain fallback language for the replacement of LIBOR or are in the process of being amended to add updated language. Finance Leases The Finance Lease balance represents our sale-leaseback transactions of rental equipment. The agreements are generally seven (7) year terms with interest rates ranging from 2.16% to 5.04%.  All of our finance leases are collateralized by our rental fleet. The net book value of the corresponding rental equipment was $620.8 million and $877.0 million as of March 31, 2022 and March 31, 2021, respectively. There were no new financing leases, as assessed under the new leasing guidance, entered into during fiscal 2022. Finance Liabilities Finance liabilities represent our rental equipment financing transactions, and we assess if sale-leaseback transactions qualify as a sale at initiation by determining if a transfer of ownership occurs.   We have determined that our equipment sale-leasebacks do not qualify as a sale, as the buyer-lessors do not obtain control of the assets in our ongoing sale-leaseback arrangements. As a result, sale-leasebacks are accounted for as a financial liability and the leased assets are capitalized at cost.     Our finance liabilities have an average term of seven (7) years and interest rates ranging from 1.60 % to 4.68 %. These finance liabilities are collateralized by our rental fleet.   The net book value of the corresponding rental equipment was $ 1,068.3 million and $ 718.3 million as of March 31, 2022 and March 31, 2021, respectively Private Placements In September 2021, AMERCO entered into a note purchase agreement to issue $ 600.0 million of fixed rate senior unsecured notes in a private placement offering.   These notes consist of four tranches each totaling $ 150.0 million and funded in September 2021.   The fixed interest rates range between 2.43 % and 2.78 % with maturities between 2029 and 2033 .   Interest is payable semiannually.   In December 2021, AMERCO entered into a note purchase agreement to issue $ 600.0 million of fixed rate senior unsecured notes in a private placement offering. These notes funded in January 2022. These notes consist of three tranches each totaling $ 100.0 million and two tranches each totaling $ 150.0 million.   The fixed interest rates range between 2.55 % and 2.88 % with maturities between 2030 and 2035 .   Interest is payable semiannually.   Other Obligations In February 2011, AMERCO and U.S. Bank, NA (the “Trustee”) entered into the U-Haul Investors Club ® Indenture.   AMERCO and the Trustee entered into this indenture to provide for the issuance of notes by us directly to investors over our proprietary website, uhaulinvestorsclub.com (“U-Notes ® ”). The U-Notes ® are secured by various types of collateral, including, but not limited to, rental equipment and real estate.   U-Notes ® are issued in smaller series that vary as to principal amount, interest rate and maturity.   U-Notes ® are obligations of the Company and secured by the associated collateral; they are not guaranteed by any of the Company’s affiliates or subsidiaries. As of March 31, 2022, the aggregate outstanding principal balance of the U-Notes ® issued was $ 88.5 million, of which $ 2.3 million is held by our insurance subsidiaries and eliminated in consolidation. Interest rates range between 1.50 % and 8.00 % and maturity dates range between 2022 and 2049 . Oxford is a member of the Federal Home Loan Bank (“FHLB”) and, as such, the FHLB has made deposits with Oxford. As of December 31, 2021, the deposits had an aggregate balance of $ 60.0 million, for which Oxford pays fixed interest rates between 0.49 % and 1.72 % with maturities between September 30, 2022 and September 29, 2025. As of December 31, 2021, available-for-sale investments held with the FHLB totaled $ 105.6 million, of which $ 62.8 million were pledged as collateral to secure the outstanding advances. The balances of these advances are included within Liabilities from investment contracts on the consolidated balance sheets. Annual Maturities of Notes, Loans and Finance Leases Payable The annual maturities of our notes, loans and finance leases payable as of March 31, 2022 for the next five years and thereafter are as follows:       Years Ended March 31,     2023   2024   2025   2026   2027   Thereafter   Total     (In thousands) Notes, loans and finance leases payable, secured $ 478,954 $ 937,542 $ 898,740 $ 570,127 $ 559,961 $ 2,614,389 $ 6,059,713