Property, Plant and Equipment Level 4 (Details) (USD $) In Thousands	Jun. 30, 2011		Mar. 31, 2011
Property, Plant and Equipment [Line Items]
Land	$ 33,292	[1]	$ 30,194	[1]
Buildings and Improvements, Gross	206,873		201,883
Machinery and Equipment, Gross	293,225		286,103
Capitalized Computer Software, Gross	103,495		101,934
Materials, Supplies, and Other	196,315		194,882
Construction in Progress, Gross	43,753	[1]	40,665	[1]
Property, Plant and Equipment, Gross	876,953		855,661
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(499,290)		(485,259)
Property, Plant and Equipment, Net	$ 377,663		$ 370,402

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