Geographic and Segment Information - Long-Lived Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Amount of identifiable long-lived assets (consisting of property, plant and equipment)	$ 996.7	$ 767.9
United States
Segment Reporting Information [Line Items]
Amount of identifiable long-lived assets (consisting of property, plant and equipment)	521.1	393.3
Thailand
Segment Reporting Information [Line Items]
Amount of identifiable long-lived assets (consisting of property, plant and equipment)	209.3	215.5
Various Other Countries
Segment Reporting Information [Line Items]
Amount of identifiable long-lived assets (consisting of property, plant and equipment)	$ 266.3	$ 159.1
Sales Revenue, Net | Geographic Concentration Risk | Located outside US, in aggregate
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	80.00%	85.00%	84.00%
Sales Revenue, Net | Geographic Concentration Risk | Europe
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	23.00%	24.00%	24.00%
Sales Revenue, Net | Geographic Concentration Risk | Asia
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	52.00%	58.00%	58.00%
Sales Revenue, Net | Geographic Concentration Risk | China
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	22.00%	30.00%	32.00%
Sales Revenue, Net | Geographic Concentration Risk | Taiwan
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	13.00%	11.00%	9.00%