Property, Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Mar. 31, 2016
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	$ 2,437,948		$ 2,437,948		$ 2,267,273
Less accumulated depreciation and amortization	1,739,244		1,739,244		1,657,877
Property, plant and equipment, net	698,704		698,704		609,396
Depreciation expense	29,700	$ 26,700	90,300	$ 77,600
Land
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	73,474		73,474		63,907
Buildings and building improvements
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	499,793		499,793		458,379
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	1,752,480		1,752,480		1,645,617
Projects in progress
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	$ 112,201		$ 112,201		$ 99,370