Historic applicable margins. This is the higher of the rate range.

No definition available.

Name:	uhal_ApplicableMarginsHighRate
Namespace Prefix:	uhal_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The debt agreement amount at the beginning of this contract. It is no longer valid because of a subsequent amendment in the terms of this loan.

+ References

No definition available.

+ Details

Name:	uhal_DebtInstrumentOriginalFaceAmount
Namespace Prefix:	uhal_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maturity date of the deposit with the Federal Home Loan Bank, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

Name:	uhal_FederalHomeLoanBankAdvancesBranchOfFhlbBankMaturityDate
Namespace Prefix:	uhal_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	uhal_FederalHomeLoanBankAdvancesBranchOfFhlbBankMaturityDateTwo
Namespace Prefix:	uhal_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of corporate (parent company) debt held by our insurance subsidiaries.

+ References

No definition available.

+ Details

Name:	uhal_SubsidiariesShareOfDebtPurchasedFromParent
Namespace Prefix:	uhal_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Equity securities categorized neither as held-to-maturity nor trading which are intended be sold more than one year from the balance sheet date or operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26626-111562

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesEquitySecuritiesNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The fair value of available-for-sale securities that serve as collateral for borrowings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5086-111524

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesPledgedAsCollateral
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The increase during the period in capital lease obligations due to entering into new capital leases.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4313-108586

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586

+ Details

Name:	us-gaap_CapitalLeaseObligationsIncurred
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13,16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

Name:	us-gaap_DebtAndCapitalLeaseObligations
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

Name:	us-gaap_DebtInstrumentInterestRateEffectivePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentInterestRateEffectivePercentageAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentageAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Latest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_DebtInstrumentMaturityDateRangeEnd1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Earliest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_DebtInstrumentMaturityDateRangeStart1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesActivityForYearAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of advances from the Federal Home Loan Bank (FHLB).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Discloses the single interest rate [if] applicable to the advances from the Federal Home Loan Bank, by branch, as of the Balance Sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtCurrentAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time.

+ References

+ Details

Name:	us-gaap_LongTermDebtPercentageBearingVariableInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a set, unchanging rate.

+ References

No definition available.

+ Details

Name:	us-gaap_LongtermDebtPercentageBearingFixedInterestAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Stated maturity date of the mortgage loan receivable on real estate, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 10
-Section S99
-Paragraph 6
-Subparagraph (SX 210.5-04.(c) Schedule IV)
-URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29)
-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

+ Details

Name:	us-gaap_MortgageLoanOnRealEstateFinalMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying amount as of the balance sheet date for the aggregate of other miscellaneous borrowings owed by the reporting entity.

+ References

+ Details

Name:	us-gaap_OtherBorrowings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The percentage charged for managing real estate properties.

+ References

No definition available.

+ Details

Name:	us-gaap_PropertyManagementFeePercentFee
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount after depreciation of long-lived, physical assets used to produce goods and services and not intended for resale, classified as other.

+ References

No definition available.

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentOtherNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_MortgagesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_MediumTermNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=uhal_FleetLoansSecuritizationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_CapitalLeaseObligationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_CollateralizedDebtObligationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=uhal_AmercoRealEstateSubsidiariesAndUhaulCompanyOfFloridaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConsolidatedEntitiesAxis=us-gaap_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=uhal_VariousSubsidiariesOfAmercoRealEstateAndUhaulIntlMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConsolidatedEntitiesAxis=us-gaap_SubsidiaryIssuerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=uhal_UhaulIntlAndSubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=uhal_RentalTruckRevolversMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=uhal_UhaulSFleetTwoThousandTenBoxTruckNoteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=uhal_AmercoUsBankNationalAssociationTrusteeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=uhal_LifeInsuranceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAxis=us-gaap_FederalHomeLoanBankOfSanFranciscoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Borrowings (Narratives) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Borrowings (Narratives) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Debt instruments, face, payment, and remaining balance amount:
Notes, loans and leases payable		$ 3,513,076	$ 3,262,880
Mortgages [Member]
Debt instruments, face, payment, and remaining balance amount:
Notes, loans and leases payable		$ 135,287	169,289
Mortgages [Member] \| Minimum [Member]
Debt instruments, issuance and maturity dates:
Mortgage loans on real estate, final maturity date		Dec. 31, 2018
Mortgages [Member] \| Maximum [Member]
Debt instruments, issuance and maturity dates:
Mortgage loans on real estate, final maturity date		Dec. 31, 2036
Senior mortgages [Member]
Debt instruments, face, payment, and remaining balance amount:
Notes, loans and leases payable		$ 1,487,645	1,292,160
Working Capital Loans [Member]
Debt instruments, face, payment, and remaining balance amount:
Notes, loans and leases payable		55,000	85,000
Rental Truck (amortizing loans) First Loan [Member]
Debt instruments, face, payment, and remaining balance amount:
Notes, loans and leases payable		342,971	324,977
Rental Truck (securitizations) [Member]
Debt instruments, face, payment, and remaining balance amount:
Notes, loans and leases payable			52,112
Capital Lease Obligations [Member]
Debt instruments, face, payment, and remaining balance amount:
Notes, loans and leases payable		984,217	876,828
Other Obligations [Member]
Debt instruments, face, payment, and remaining balance amount:
Notes, loans and leases payable		$ 73,579	69,867
Amerco Real Estate Subsidiaries and Uhaul Company of Florida [Member] \| Mortgages [Member] \| Amerco [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage		6.93%
Debt instruments, interest rate, effective percentage:
LIBOR		1.74%
Applicable margin interest rate		1.50%
Debt instrument at period end, LIBOR plus margin		1.50%
Sum of LIBOR and margin, maximum rate		3.24%
Debt instruments, face, payment, and remaining balance amount:
Amounts held at LIBOR plus margin		$ 73,900
Line of credit facility, remaining borrowing capacity		61,400
Notes, loans and leases payable		$ 135,300
Debt instruments, issuance and maturity dates:
Mortgage loans on real estate, final maturity date		Apr. 30, 2023
Debt instrument, maturity date		Aug. 30, 2018
Various Subsidiaries of Amerco Real Estate and Uhaul Intl [Member] \| Senior mortgages [Member] \| Uhaul International, Inc and AMERCO [Member]
Debt instruments, face, payment, and remaining balance amount:
Notes, loans and leases payable		$ 1,487,600
Debt instruments, issuance and maturity dates:
Debt instrument, maturity date range, start		Jan. 01, 2021
Debt instrument, maturity date range, end		Dec. 31, 2038
Various Subsidiaries of Amerco Real Estate and Uhaul Intl [Member] \| Senior mortgages [Member] \| Uhaul International, Inc and AMERCO [Member] \| Minimum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage		3.72%
Various Subsidiaries of Amerco Real Estate and Uhaul Intl [Member] \| Senior mortgages [Member] \| Uhaul International, Inc and AMERCO [Member] \| Maximum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage		6.62%
Various Subsidiaries of Amerco Real Estate and Uhaul Intl [Member] \| Working Capital Loans [Member] \| Amerco [Member]
Debt instruments, interest rate, effective percentage:
LIBOR		1.65%
Applicable margin interest rate		1.50%
Sum of LIBOR and margin, maximum rate		3.15%
Debt instruments, face, payment, and remaining balance amount:
Line of credit facility, maximum borrowing capacity		$ 55,000
Notes, loans and leases payable		$ 55,000
Debt instruments, issuance and maturity dates:
Debt instrument, maturity date		Nov. 30, 2018
Various Subsidiaries of Amerco Real Estate and Uhaul Intl [Member] \| Working capital loans two [Member] \| Amerco [Member]
Debt instruments, interest rate, effective percentage:
Unused capacity fee		0.30%
Debt instruments, face, payment, and remaining balance amount:
Debt instrument, original face amount		$ 150,000
Line of credit facility, maximum borrowing capacity		300,000
Line of credit facility, remaining borrowing capacity		$ 150,000
Debt instruments, issuance and maturity dates:
Debt instrument, maturity date		Sep. 30, 2020
Various Subsidiaries of Amerco Real Estate and Uhaul Intl [Member] \| Working capital loans two [Member] \| Amerco [Member] \| Minimum [Member]
Debt instruments, interest rate, effective percentage:
Sum of LIBOR and margin, maximum rate		1.38%
Various Subsidiaries of Amerco Real Estate and Uhaul Intl [Member] \| Working capital loans two [Member] \| Amerco [Member] \| Maximum [Member]
Debt instruments, interest rate, effective percentage:
Sum of LIBOR and margin, maximum rate		1.50%
Uhaul Intl and Subsidiaries [Member] \| Rental Truck (amortizing loans) First Loan [Member] \| Uhaul International, Inc and AMERCO [Member]
Debt instruments, face, payment, and remaining balance amount:
Notes, loans and leases payable		$ 343,000
Debt instruments, issuance and maturity dates:
Debt instrument, maturity date range, start		Jun. 01, 2018
Debt instrument, maturity date range, end		Mar. 31, 2025
Uhaul Intl and Subsidiaries [Member] \| Rental Truck (amortizing loans) First Loan [Member] \| Uhaul International, Inc and AMERCO [Member] \| Minimum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage		2.82%
Debt instruments, interest rate, effective percentage:
LIBOR		1.66%
Applicable margin interest rate		1.72%
Uhaul Intl and Subsidiaries [Member] \| Rental Truck (amortizing loans) First Loan [Member] \| Uhaul International, Inc and AMERCO [Member] \| Maximum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage		4.76%
Debt instruments, interest rate, effective percentage:
LIBOR		1.78%
Applicable margin interest rate		2.38%
Uhaul Intl and Subsidiaries [Member] \| Rental Truck (amortizing loans) Second Loan [Member] \| Uhaul International, Inc and AMERCO [Member]
Debt instruments, face, payment, and remaining balance amount:
Amount held at fixed interest rate		$ 288,200
Uhaul Intl and Subsidiaries [Member] \| Rental Truck (amortizing loans) Second Loan [Member] \| Uhaul International, Inc and AMERCO [Member] \| Minimum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage		1.95%
Uhaul Intl and Subsidiaries [Member] \| Rental Truck (amortizing loans) Second Loan [Member] \| Uhaul International, Inc and AMERCO [Member] \| Maximum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage		3.94%
Uhaul Intl and Subsidiaries [Member] \| Rental Truck Revolvers [Member]
Debt instruments, interest rate, effective percentage:
Applicable margin interest rate		1.15%
Debt instruments, face, payment, and remaining balance amount:
Debt instrument, original face amount		$ 490,000
Line of credit facility, maximum borrowing capacity		565,000
Notes, loans and leases payable		$ 460,000
Debt instruments, issuance and maturity dates:
Debt instrument, maturity date range, start		Mar. 01, 2020
Debt instrument, maturity date range, end		Nov. 30, 2021
Uhaul Intl and Subsidiaries [Member] \| Rental Truck Revolvers [Member] \| Minimum [Member]
Debt instruments, interest rate, effective percentage:
LIBOR		1.65%
Sum of LIBOR and margin, maximum rate		2.80%
Uhaul Intl and Subsidiaries [Member] \| Rental Truck Revolvers [Member] \| Maximum [Member]
Debt instruments, interest rate, effective percentage:
LIBOR		1.66%
Sum of LIBOR and margin, maximum rate		2.81%
Uhaul Intl and Subsidiaries [Member] \| Capital Lease Obligations [Member]
Debt instruments, face, payment, and remaining balance amount:
New capital lease obligations, amount		$ 397,000
Notes, loans and leases payable		984,200	876,800
Capitalized assets, net book value		$ 1,407,600	$ 1,233,300
Uhaul S Fleet Two Thousand Ten Box Truck Note [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage		4.90%
Debt instruments, face, payment, and remaining balance amount:
Debt instrument, original face amount		$ 155,000
Debt instruments, issuance and maturity dates:
Debt instrument, maturity date		Oct. 31, 2017
Amerco, Us Bank, National Association, Trustee [Member] \| Other Obligations [Member]
Debt instruments, face, payment, and remaining balance amount:
Notes, loans and leases payable		$ 77,300
Subsidiary holdings of parent company debt		$ 3,800
Debt instruments, issuance and maturity dates:
Debt instrument, maturity date range, start		Jan. 01, 2018
Debt instrument, maturity date range, end		Dec. 31, 2047
Amerco, Us Bank, National Association, Trustee [Member] \| Other Obligations [Member] \| Minimum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage		2.75%
Amerco, Us Bank, National Association, Trustee [Member] \| Other Obligations [Member] \| Maximum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage		8.00%
Life Insurance [Member] \| FHLB [Member]
Federal Home Loan Bank, Advances, Activity for the year [Abstract]
Deposit amount	$ 60,000
Deposit earliest maturity date	Mar. 29, 2018
Deposit latest maturity date	Mar. 30, 2020
Available for sale equity securities, noncurrent	$ 129,200
Available for sale equity securities pledged as collateral	$ 73,100
Life Insurance [Member] \| FHLB [Member] \| Minimum [Member]
Federal Home Loan Bank, Advances, Activity for the year [Abstract]
Deposit interest rate	1.33%
Life Insurance [Member] \| FHLB [Member] \| Maximum [Member]
Federal Home Loan Bank, Advances, Activity for the year [Abstract]
Deposit interest rate	1.75%