The expense charged against earnings on various costs associated with terminated proposal to acquire another entity.

Name:	mchp_ExpensesOnVariousCostsAssociatedWithTerminatedProposal
Namespace Prefix:	mchp
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	mchp_NotesToFinancialStatementsAbstract
Namespace Prefix:	mchp
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Office closing and severance related costs associated with the acquisition of SST

+ Details

Name:	mchp_OfficeClosingAndSeveranceRelatedCostsAssociatedWithAcquisition
Namespace Prefix:	mchp
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Value per share (such as common shares, preferred shares, or partnership interest) issued or issuable to acquire the entity.

+ Details

Name:	mchp_ProposedBusinessAcquisitionAmountPerShare
Namespace Prefix:	mchp
Data Type:	us-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Value of equity interests (such as common shares, preferred shares, or partnership interest) issued or issuable to acquire the entity.

+ Details

Name:	mchp_ProposedBusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned
Namespace Prefix:	mchp
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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.

+ Details

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The useful life of all finite-lived intangible assets. This may be stated as a fixed number (for example, 10 years) if all assets have the same useful life, or it can be stated in a range (for example, six to eight years) if there is a range of useful lives in the asset group.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 142
-Paragraph 12, 13, 14

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsUsefulLife
Namespace Prefix:	us-gaap
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the expenses incurred by the entity which are directly related and attributable to receiving an award in settlement of litigation.

+ Details

Name:	us-gaap_LitigationSettlementExpense
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents the gross amount awarded, to be received by, or to be remitted to the entity in settlement of litigation occurring during the period.

+ Details

Name:	us-gaap_LitigationSettlementGross
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Carrying amount as of the balance sheet date of amounts paid for royalties in advance of when the expense should be recognized, which will occur within one year or in the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 43
-Chapter 3
-Section A
-Paragraph 4

+ Details

Name:	us-gaap_PrepaidRoyalties
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of purchased research and development assets that are acquired in a business combination have no alternative future use and are therefore written off in the period of acquisition.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141
-Paragraph 51
-Subparagraph g

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 4
-Paragraph 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 2
-Paragraph 13

+ Details

Name:	us-gaap_ResearchAndDevelopmentInProcess
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Special Charges (Details) (USD $)	3 Months Ended				12 Months Ended		3 Months Ended
Special Charges (Details) (USD $)	Mar. 31, 2011	Sep. 30, 2009	Jun. 30, 2009	Mar. 31, 2009	Mar. 31, 2011	Mar. 31, 2010	Dec. 31, 2008 Acquisition of Hampshire Company [Member]	Dec. 31, 2008 Acquisition of HI-TECH Software [Member]	Dec. 31, 2008 Acquisition of R and E International [Member]
Notes to Financial Statements [Abstract]
Total payment on settlement on alleged infringement claims	$ 2,750,000	$ 1,400,000		$ 8,250,000
Settlement on infringement claims expensed			1,200,000	4,000,000
Settlement payments recorded on prepaid royalty	2,750,000		200,000	4,250,000	2,750,000
Estimated remaining life of the patents (in years)				20
Proposed amount per share to acquire Atmel (in dollars per share)						$ 5.00
Proposed total amount to acquire Atmel						2,300,000,000
Expenses on various costs associated with terminated proposal						1,600,000
Business Acquisition [Line Items]
Incurred in-process research and development charge on acquisition							500,000	200,000	200,000
Office closing and severance related costs associated with the acquisition of SST					$ 1,900,000