Debt and Credit Facility - Conversion Features (Details)	3 Months Ended	12 Months Ended
Mar. 31, 2019	Mar. 31, 2019 USD ($) day
Debt Instrument [Line Items]
If-converted value in excess of principal \| $		$ 1,000
2015 Senior Convertible Debt
Debt Instrument [Line Items]
Threshold percentage of stock price trigger	130.00%
If-converted value in excess of principal \| $		$ 857,900,000
Convertible Debt
Debt Instrument [Line Items]
Debt instrument, redemption price, percentage		100.00%
Convertible Debt \| Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Threshold percentage of stock price trigger		130.00%
Threshold trading days		20
Threshold consecutive trading days		30
Convertible Debt \| Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Threshold percentage of stock price trigger		98.00%
Threshold trading days		5
Threshold consecutive trading days		10

The amount by which the convertible debt's if-converted value exceeds its principle amount at the balance sheet date, regardless of whether the instrument is currently convertible. This element applies to public companies only.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031898-161870

+ Details

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

- Definition

Threshold period of specified consecutive trading days within which common stock price to conversion price of convertible debt instrument must exceed threshold percentage for specified number of trading days to trigger conversion feature.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum percentage of common stock price to conversion price of convertible debt instruments to determine eligibility of conversion.

+ References

No definition available.

+ Details

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

- Definition

Threshold number of specified trading days that common stock price to conversion price of convertible debt instruments must exceed threshold percentage within a specified consecutive trading period to trigger conversion feature.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentConvertibleThresholdTradingDays
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
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_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

+ Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=mchp_A2015SeniorSubordinatedConvertibleDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: