v3.8.0.1

Pension Plans (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Retirement Benefits [Abstract]
Expected periodic pension cost in current fiscal year			$ 2.6
Benefits paid	$ 0.2	$ 0.1	0.3	$ 0.2
Defined benefit plan expected contributions in current fiscal year			$ 0.7

X

- Definition

Represents the aggregate of expected contributions by employer in the current fiscal year.

+ References

No definition available.

+ Details

Name:	mchp_DefinedBenefitPlanExpectedContributionsByEmployerInCurrentFiscalYear
Namespace Prefix:	mchp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

The total amount of expected net periodic benefit cost for defined benefit plans for the current fiscal year. Period benefit costs include the following components: service cost, interest cost, prior service cost or credit, actuarial gain (loss), gain (loss) due to settlements or curtailments.

+ References

No definition available.

+ Details

Name:	mchp_DefinedBenefitPlanNetPeriodicBenefitCostExpectedInCurrentFiscalYear
Namespace Prefix:	mchp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- References

No definition available.

+ Details

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

X

- Definition

Amount of payment to participant of defined benefit plan which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 60
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6414203&loc=d3e39716-114964

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)(6)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

+ Details

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