Quarterly Results (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 543,207	$ 528,710	$ 546,243	$ 528,876	$ 493,384	$ 482,372	$ 492,669	$ 462,792	$ 2,147,036	$ 1,931,217	$ 1,581,623
Gross profit	313,632	301,959	307,454	306,519	290,586	282,720	288,863	266,574	1,229,564	1,128,743	838,459
Operating income	110,347	98,009	101,318	115,946	126,037	116,918	117,508	98,401	425,620	458,864	178,553
Net income	98,580	84,798	92,038	89,909	111,495	105,401	99,806	78,579	365,325	395,281	127,389
Less: Net loss attributable to noncontrolling interests	822	1,259	1,603	0					3,684	0	0
Net income attributable to Microchip Technology	99,402	86,057	93,641	89,909					369,009	395,281	127,389
Diluted net income per common share attributable to Microchip Technology stockholders	$ 0.45	$ 0.39	$ 0.42	$ 0.40	$ 0.50	$ 0.48	$ 0.46	$ 0.37	$ 1.65	$ 1.82	$ 0.62
Loss on retirement of junior convertible debentures									50,631	0	0
Realized gain on available-for-sale investments									$ 18,469	$ 0	$ 0