Net income per common share attributable to Microchip Technology Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended				12 Months Ended
	Feb. 28, 2017	Feb. 28, 2015	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income attributable to Microchip Technology			$ 67,355	$ 61,211	$ 64,899	$ 130,667	$ 164,639	$ 324,132	$ 369,009
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest							$ 170,592	$ 324,132	$ 369,009
Weighted average common shares outstanding							217,196,000	203,384,000	200,937,000
Dilutive effect of stock options and RSUs							4,357,000	3,350,000	3,642,000
Weighted average common and potential common shares outstanding							234,806,000	217,388,000	223,561,000
Net income from continuing operations (in usd per share)							$ 0.79	$ 1.59	$ 1.84
Net income from continuing operations (in usd per share)							$ 0.73	$ 1.49	$ 1.65
Number of antidilutive option shares (in shares)							0	298,015
2007 Junior Subordinated Convertible Notes
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dilutive effect of subordinated convertible debentures							12,714,831	10,654,070	18,982,440
Weighted average conversion price per share used in calculating dilutive effect of convertible debt amount per share							$ 24.01	$ 24.73	$ 25.48
2015 Senior Subordinated Convertible Debt
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dilutive effect of subordinated convertible debentures							538,044	0	0
Weighted average conversion price per share used in calculating dilutive effect of convertible debt amount per share							$ 65.21	$ 67.19	$ 68.25
2017 Senior Subordinated Convertible Debt
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dilutive effect of subordinated convertible debentures							0	0	0
Weighted average conversion price per share used in calculating dilutive effect of convertible debt amount per share							$ 100.58	$ 0.00	$ 0.00
2017 Junior Subordinated Convertible Debt
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dilutive effect of subordinated convertible debentures							0	0	0
Weighted average conversion price per share used in calculating dilutive effect of convertible debt amount per share							$ 98.81	$ 0.00	$ 0.00
Long-term Debt | 2007 Junior Subordinated Convertible Notes
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Shares issued to settle convertible debt	11,997,924
Extinguishment of debt, amount	$ 431,300	$ 575,000