CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Net sales		$ 994,205	$ 834,366	$ 2,978,485	$ 2,505,141
Cost of sales	[1]	387,146	369,107	1,172,893	1,280,771
Gross profit		607,059	465,259	1,805,592	1,224,370
Research and development	[1]	131,555	132,433	395,656	418,111
Selling, general and administrative	[1]	109,059	111,017	337,620	388,651
Amortization of acquired intangible assets		121,003	82,791	362,761	243,356
Special charges and other, net		196	20,944	17,312	52,522
Operating expenses		361,813	347,185	1,113,349	1,102,640
Operating income		245,246	118,074	692,243	121,730
Losses on equity method investment		(56)	(55)	(167)	(167)
Other income (expense):
Interest income		6,306	501	14,441	1,765
Interest expense		(49,744)	(35,143)	(148,693)	(104,685)
Loss on settlement of convertible debt		(2,140)	0	(15,966)	0
Other (loss) income, net		(2,962)	121	7,233	(658)
Income before income taxes		196,650	83,498	549,091	17,985
Income tax provision (benefit)		447,736	(23,837)	440,434	(15,699)
Net (loss) income from continuing operations		(251,086)	107,335	108,657	33,684
Loss from discontinued operations		0	(191)	0	(7,514)
Income tax benefit		0	(31)	0	(1,561)
Net loss from discontinued operations		0	(160)	0	(5,953)
Net (loss) income		$ (251,086)	$ 107,175	$ 108,657	$ 27,731
Basic net (loss) income per common share
Basic net income (loss) from continuing operations, per common share (in USD per share)		$ (1.07)	$ 0.50	$ 0.47	$ 0.16
Basic net loss from discontinued operations, per common share (in USD per share)		0.00	0.00	0.00	(0.03)
Basic net income (loss) attributable to Microchip Technology, per common share (in USD per share)		(1.07)	0.50	0.47	0.13
Diluted net (loss) income per common share
Diluted net income (loss) from continuing operations, per common share (in USD per share)		(1.07)	0.46	0.44	0.14
Diluted net loss from discontinued operations, per common share (in USD per share)		0.00	0.00	0.00	(0.02)
Diluted net income (loss) attributable to Microchip Technology, per common share (in USD per share)		(1.07)	0.46	0.44	0.12
Dividends declared per common share (in USD per share)		$ 0.3625	$ 0.3605	$ 1.0860	$ 1.0800
Basic common shares outstanding		234,106	216,210	232,278	215,360
Diluted common shares outstanding		234,106	235,424	248,024	233,351

[1] Includes share-based compensation expense as follows:Cost of sales 3,494 3,468 10,587 15,465 Research and development 10,921 9,881 31,797 37,569 Selling, general and administrative 9,588 8,771 27,637 53,055