Property, Plant and Equipment Level 4 (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011		Mar. 31, 2011
Property, Plant and Equipment [Line Items]
Land	$ 32,629	[1]	$ 30,194	[1]
Buildings and Improvements, Gross	221,249		201,883
Machinery and Equipment, Gross	302,210		286,103
Capitalized Computer Software, Gross	107,477		101,934
Materials, Supplies, and Other	206,470		194,882
Construction in Progress, Gross	26,478	[1]	40,665	[1]
Property, Plant and Equipment, Gross	896,513		855,661
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(518,348)		(485,259)
Property, Plant and Equipment, Net	$ 378,165		$ 370,402

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