Revenue and Assets by Geographic Segment (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Segment Reporting Information [Line Items]
Amount of identifiable long-lived assets (consisting of property, plant and equipment)	$ 516,611	$ 540,513
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales from largest distributor (in hundredths)	10.00%	10.00%	12.00%
United States [Member]
Segment Reporting Information [Line Items]
Amount of identifiable long-lived assets (consisting of property, plant and equipment)	314,339	330,046
Thailand [Member]
Segment Reporting Information [Line Items]
Amount of identifiable long-lived assets (consisting of property, plant and equipment)	186,098	193,729
All other countries except United States and Thailand [Member]
Segment Reporting Information [Line Items]
Amount of identifiable long-lived assets (consisting of property, plant and equipment)	$ 16,174	$ 16,738
Located outside US, in aggregate [Member]
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	82.00%	80.00%	77.00%
Europe [Member]
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	23.00%	23.00%	25.00%
Asia [Member]
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	56.00%	57.00%	51.00%
China, including Hong-Kong [Member]
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	24.00%	25.00%	25.00%
Taiwan [Member]
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	15.00%	13.00%	10.00%