The latest maturity year for these debt instruments.

No definition available.

Name:	uhal_MaturityEndYear
Namespace Prefix:	uhal_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

- Definition

The earliest maturity year for these debt instruments.

+ References

No definition available.

+ Details

Name:	uhal_MaturityStartYear
Namespace Prefix:	uhal_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

- Definition

The DebtInstrumentMaturityDate could have worked for this element, but it must include the format Month-Date-Year. Will use this US-GAAP Element in the next few schedules, when possible, where we break down the various items that make up the Borrowing's narrative.

+ References

No definition available.

+ Details

Name:	uhal_MaturityYear
Namespace Prefix:	uhal_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of accumulated amortization of debt issuance costs classified as noncurrent.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28555-108399

+ Details

Name:	us-gaap_AccumulatedAmortizationOfNoncurrentDeferredFinanceCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

Amount, before accumulated amortization, of debt issuance costs classified as noncurrent. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

+ Details

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

- Definition

Amount, after accumulated amortization, of debt issuance costs classified as noncurrent. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28555-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtByMaturityAbstract
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 set, unchanging rate.

+ References

+ Details

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

- Details

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

- Details

Name:	srt_RangeAxis=srt_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:	srt_RangeAxis=srt_MinimumMember
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_FleetLoansRevolvingCreditMember
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=uhal_FinanceLeaseMember
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:

Borrowings (Long-term Debt Borrowings) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Mar. 31, 2020
Debt instrument, maturities:
Notes, loans and finance/capital leases payable	$ 4,731,768	$ 4,731,768	$ 4,651,068
Less: Debt issuance costs	(30,543)	(30,543)	(29,777)
Total notes, loans and finance/capital leases payable, net	$ 4,701,225	$ 4,701,225	$ 4,621,291
Real estate loan (amortizing term) [Member]
Debt instrument, maturities:
Debt instrument, maturity year	2023
Real estate loan (amortizing term) [Member] \| Maximum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage	1.66%	1.66%
Senior Mortgages [Member]
Debt instrument, maturities:
Debt instrument, maturity year range, start	2021
Debt instrument, maturity year range, end	2038
Senior Mortgages [Member] \| Minimum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage	3.11%	3.11%
Senior Mortgages [Member] \| Maximum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage	6.62%	6.62%
Real estate loans (revolving credit) [Member]
Debt instrument, maturities:
Debt instrument, maturity year	2025
Debt instrument, maturity year range, start	2022
Real estate loans (revolving credit) [Member] \| Minimum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage	1.56%	1.56%
Real estate loans (revolving credit) [Member] \| Maximum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage	3.25%	3.25%
Fleet loans (amortizing term) [Member]
Debt instrument, maturities:
Debt instrument, maturity year range, start	2020
Debt instrument, maturity year range, end	2027
Fleet loans (amortizing term) [Member] \| Minimum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage	2.04%	2.04%
Fleet loans (amortizing term) [Member] \| Maximum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage	4.66%	4.66%
Fleet loans (revolving credit) [Member]
Debt instrument, maturities:
Debt instrument, maturity year range, start	2022
Debt instrument, maturity year range, end	2024
Fleet loans (revolving credit) [Member] \| Minimum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage	1.31%	1.31%
Fleet loans (revolving credit) [Member] \| Maximum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage	2.36%	2.36%
Capital Leases (rental equipment) [Member]
Debt instrument, maturities:
Debt instrument, maturity year range, start	2020
Debt instrument, maturity year range, end	2026
Capital Leases (rental equipment) [Member] \| Minimum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage	1.92%	1.92%
Capital Leases (rental equipment) [Member] \| Maximum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage	5.04%	5.04%
Finance capital lease [Member]
Debt instrument, maturities:
Debt instrument, maturity year	2028
Debt instrument, maturity year range, start		2020
Finance capital lease [Member] \| Minimum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage	1.60%	1.60%
Finance capital lease [Member] \| Maximum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage	4.22%	4.22%
Other Obligations [Member]
Debt instrument, maturities:
Debt instrument, maturity year range, start	2020
Debt instrument, maturity year range, end	2049
Other Obligations [Member] \| Minimum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage	2.50%	2.50%
Other Obligations [Member] \| Maximum [Member]
Debt instruments, interest rate, stated percentage:
Debt instrument, interest rate, stated percentage	8.00%	8.00%