Property, Plant and Equipment Level 4 (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Mar. 31, 2012
Property, Plant and Equipment [Line Items]
Land	$ 35,032	[1]	$ 33,099	[1]
Buildings and Improvements, Gross	236,734		230,823
Machinery and Equipment, Gross	306,858		301,665
Capitalized Computer Software, Gross	107,625		110,130
Materials, Supplies, and Other	226,616		210,899
Construction in Progress, Gross	41,904	[1]	22,811	[1]
Property, Plant and Equipment, Gross	954,769		909,427
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(541,006)		(523,018)
Property, Plant and Equipment, Net	$ 413,763		$ 386,409

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