Unobservable Input Reconciliation Liabilities (Details) (Contingent consideration [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Contingent consideration [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	$ 19,100	$ 0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	(1,370)	(4,400)
Purchases, sales, issuances and settlements, net	(20,470)
mchp_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityAcquisitionRelatedAdditions		14,700
Fair value, measurements with unobservable inputs reconciliation, ending	$ 0	$ 19,100