Shareholders' Equity - Summary of Restricted Stock Awards and Restricted Stock Units Activity (Details) - shares	12 Months Ended
Apr. 30, 2016	May 02, 2015	May 03, 2014	Apr. 28, 2012	Apr. 30, 2011
2014 Incentive Plan \| RSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested and unissued - beginning balance (in shares)	0	0
Awarded (in shares)	1,185,000	13,500
Vested (in shares)	(24,000)	(13,500)
Forfeited and cancelled (in shares)	0	0
Unvested and unissued - ending balance (in shares)	1,161,000	0	0
2014 Incentive Plan \| RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested and unissued - beginning balance (in shares)	0	0
Awarded (in shares)	576,000	0
Vested (in shares)	0	0
Forfeited and cancelled (in shares)	0	0
Unvested and unissued - ending balance (in shares)	576,000	0	0
2010 Stock Plan \| RSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested and unissued - beginning balance (in shares)	66,667	700,000	700,000
Awarded (in shares)	0	0	0	100,000	640,000
Vested (in shares)	(33,333)	(633,333)	0
Forfeited and cancelled (in shares)	0	0	0
Unvested and unissued - ending balance (in shares)	33,334	66,667	700,000
2010 Stock Plan \| RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested and unissued - beginning balance (in shares)	0	60,000	120,000
Awarded (in shares)	0	0	0		320,000
Vested (in shares)	0	(60,000)	(60,000)
Forfeited and cancelled (in shares)	0	0	0
Unvested and unissued - ending balance (in shares)	0	0	60,000
2007 Stock Plan \| RSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested and unissued - beginning balance (in shares)	0	0	0
Awarded (in shares)	0	13,500	27,000
Vested (in shares)	0	(13,500)	(27,000)
Forfeited and cancelled (in shares)	0	0	0
Unvested and unissued - ending balance (in shares)	0	0	0

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(2)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_PlanNameAxis=mei_TwoThousandFourteenStockPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=mei_TwoThousandTenStockPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=mei_TwoThousandSevenStockPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: