Accounting for Derivatives (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Foreign Exchange Forward | Other (income) expense, net
Derivative instruments in the Company's Condensed Consolidated Financial Statements
Loss (gain) on Derivatives	$ (2,652)	$ (6,051)	$ 823
Foreign Exchange Forward | Current assets
Derivative instruments in the Company's Condensed Consolidated Financial Statements
Fair Value of Derivative Assets	0	104
Foreign Exchange Forward | Current liabilities
Derivative instruments in the Company's Condensed Consolidated Financial Statements
Fair Value of Derivative Liabilities	25	5,725
Commodity swap | Cost of Sales
Derivative instruments in the Company's Condensed Consolidated Financial Statements
Loss (gain) on Derivatives	1,302	3,970	(16)
Commodity swap | Current assets
Derivative instruments in the Company's Condensed Consolidated Financial Statements
Fair Value of Derivative Assets	141	320
Commodity swap | Current liabilities
Derivative instruments in the Company's Condensed Consolidated Financial Statements
Fair Value of Derivative Liabilities	0	697
Interest Rate Swaps | Interest expense, net
Derivative instruments in the Company's Condensed Consolidated Financial Statements
Loss (gain) on Derivatives	(2,053)	(1,820)	5,305
Interest Rate Swaps | Current assets
Derivative instruments in the Company's Condensed Consolidated Financial Statements
Fair Value of Derivative Assets	0	1,755
Interest Rate Swaps | Noncurrent assets
Derivative instruments in the Company's Condensed Consolidated Financial Statements
Fair Value of Derivative Assets	$ 0	$ 2,323