Property, Plant and Equipment (Details) (USD $)	12 Months Ended
Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Property, Plant and Equipment [Line Items]
Property, plant, and equipment costs	$ 1,897,685,000	$ 1,818,550,000
Accumulated depreciation	1,383,141,000	1,301,939,000
Property, plant and equipment, net	514,544,000	516,611,000
Depreciation expense	88,300,000	86,400,000	92,700,000
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment costs	47,102,000	46,529,000
Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment costs	396,611,000	374,042,000
Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment costs	1,377,814,000	1,314,303,000
Projects in progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment costs	$ 76,158,000	$ 83,676,000

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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- Definition

Gross amount of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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- Definition

Amount, net of accumulated depreciation, depletion and amortization, of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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