Net income per common share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]
Net income attributable to Microchip Technology	$ 93,641	$ 99,806	$ 183,550	$ 178,385
Weighted average common shares outstanding	200,629,000	197,825,000	200,408,000	197,388,000
Dilutive effect of stock options and RSUs	3,767,000	4,144,000	3,780,000	3,908,000
Dilutive effect of convertible debt	20,887,608	14,506,100	20,717,720	13,075,168
Weighted average common and potential common shares outstanding	225,284,000	216,475,000	224,906,000	214,371,000
Basic net income per common share attributable to Microchip Technology stockholders	$ 0.47	$ 0.50	$ 0.92	$ 0.90
Diluted net income per common share attributable to Microchip Technology stockholders	$ 0.42	$ 0.46	$ 0.82	$ 0.83
Weighted average conversion price per share used in calculating dilutive effect of convertible debt (amount per share)	$ 25.58	$ 26.42	$ 25.67	$ 26.54
Number of antidilutive option shares (in shares)	0	0	0	0