Property, Plant and Equipment Level 4 (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014		Mar. 31, 2014
Property, Plant and Equipment [Line Items]
Land	$ 35,643	[1]	$ 33,601	[1]
Buildings and Improvements, Gross	268,487		256,879
Machinery and Equipment, Gross	373,624		360,977
Capitalized Computer Software, Gross	102,849		100,349
Materials, Supplies, and Other	280,126		258,547
Construction in Progress, Gross	33,904	[1]	35,016	[1]
Property, Plant and Equipment, Gross	1,094,633		1,045,369
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(619,148)		(590,959)
Property, Plant and Equipment, Net	$ 475,485		$ 454,410

[1] Land is not depreciated. Construction in progress is not depreciated until placed in service.