Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Segment reporting information [Line Items]
Net Sales	$ 994,205	$ 834,366	$ 2,978,485	$ 2,505,141
Gross Profit	607,059	465,259	1,805,592	1,224,370
Semiconductor products
Segment reporting information [Line Items]
Net Sales	966,678	810,532	2,900,145	2,437,049
Gross Profit	579,532	441,425	1,727,252	1,156,278
Technology licensing
Segment reporting information [Line Items]
Net Sales	27,527	23,834	78,340	68,092
Gross Profit	$ 27,527	$ 23,834	$ 78,340	$ 68,092