Property, Plant and Equipment Level 4 (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Mar. 31, 2013
Property, Plant and Equipment [Line Items]
Land	$ 34,400	[1]	$ 36,355	[1]
Buildings and Improvements, Gross	249,165		242,885
Machinery and Equipment, Gross	350,560		331,953
Capitalized Computer Software, Gross	101,336		96,567
Materials, Supplies, and Other	255,753		237,516
Construction in Progress, Gross	38,463	[1]	36,032	[1]
Property, Plant and Equipment, Gross	1,029,677		981,308
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(584,731)		(549,356)
Property, Plant and Equipment, Net	$ 444,946		$ 431,952

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