Area of facility.

No definition available.

Name:	mpaa_AreaOfFacility
Namespace Prefix:	mpaa_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of gain (loss) on the remeasurement of lease liabilities.

+ References

No definition available.

+ Details

Name:	mpaa_GainLossOnRemeasurementOfLeaseLiabilities
Namespace Prefix:	mpaa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The increase (decrease) during the reporting period in the aggregate amount of liabilities that result from activities related to leases.

+ References

No definition available.

+ Details

Name:	mpaa_IncreaseDecreaseInOperatingLeaseLiability
Namespace Prefix:	mpaa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Term of option to extend lessee's operating and finance leases in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	mpaa_LesseeOperatingLeaseAndFinanceLeaseOptionToExtendTerm
Namespace Prefix:	mpaa_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Maturity date of lessee's operating lease not yet commenced.

+ References

No definition available.

+ Details

Name:	mpaa_LesseeOperatingLeaseLeaseNotYetCommencedMaturityDate
Namespace Prefix:	mpaa_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of lessee's undiscounted obligation for lease payments for lease not yet commenced.

+ References

No definition available.

+ Details

Name:	mpaa_LesseeOperatingLeaseLeaseNotYetCommencedMinimumLeasePayment
Namespace Prefix:	mpaa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The number of buildings for a operating lease which has been executed but not yet commenced.

+ References

No definition available.

+ Details

Name:	mpaa_OperatingLeaseLeaseNotYetCommencedNumberOfBuildings
Namespace Prefix:	mpaa_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

Term of lessee's finance lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980

+ Details

Name:	us-gaap_LesseeFinanceLeaseTermOfContract1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=mpaa_OfficeAndManufacturingMember
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:	srt_StatementGeographicalAxis=country_MX
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_ManufacturingFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=country_CA
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Leases, General Information (Details)	12 Months Ended
Leases, General Information (Details)	Mar. 31, 2020 USD ($) ft² Building	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)
Leases [Abstract]
Loss in foreign currency-denominated lease liabilities	$ (11,710,000)	$ 0	$ 0
Maximum [Member]
Leases [Abstract]
Option to extend, term	5 years
Office and Manufacturing Equipment [Member] \| Minimum [Member]
Leases [Abstract]
Finance leases term	3 years
Office and Manufacturing Equipment [Member] \| Maximum [Member]
Leases [Abstract]
Finance leases term	5 years
Mexico [Member]
Leases [Abstract]
Number of buildings under lease not yet commenced \| Building	1
Lease expiration date	Dec. 31, 2032
Lease payments, lease not yet commenced	$ 12,538,000
Mexico [Member] \| Remanufacturing Facility [Member]
Leases [Abstract]
Area of facility \| ft²	199,000
Increase in operating lease liability	$ 16,245,000
Canada [Member]
Leases [Abstract]
Number of buildings under lease not yet commenced \| Building	1
Lease expiration date	May 31, 2023
Lease payments, lease not yet commenced	$ 4,299,000