Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment reporting information [Line Items]
Net Sales	$ 541,391	$ 546,243	$ 1,075,343	$ 1,075,119
Gross Profit	300,950	307,454	609,967	613,973
Semiconductor products [Member]
Segment reporting information [Line Items]
Net Sales	518,216	523,659	1,028,905	1,032,098
Gross Profit	277,775	284,870	563,529	570,952
Technology licensing [Member]
Segment reporting information [Line Items]
Net Sales	23,175	22,584	46,438	43,021
Gross Profit	$ 23,175	$ 22,584	$ 46,438	$ 43,021