Revenue and Assets by Geographic Segment (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]
Amount of identifiable long-lived assets (consisting of property, plant and equipment)	581,572	531,967
United States [Member]
Segment Reporting Information [Line Items]
Amount of identifiable long-lived assets (consisting of property, plant and equipment)	331,372	311,926
Thailand [Member]
Segment Reporting Information [Line Items]
Amount of identifiable long-lived assets (consisting of property, plant and equipment)	197,981	179,139
Various Other Countries besides United States and Thailand [Member]
Segment Reporting Information [Line Items]
Amount of identifiable long-lived assets (consisting of property, plant and equipment)	52,219	40,902
Located outside US, in aggregate [Member]
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	84.00%	84.00%	83.00%
Europe [Member]
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	21.00%	21.00%	22.00%
Asia [Member]
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	59.00%	60.00%	58.00%
China, including Hong-Kong [Member]
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	28.00%	29.00%	27.00%
Taiwan [Member]
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	14.00%	13.00%	13.00%