Additional Consolidated Balance Sheets Information Level 4 (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Mar. 31, 2012
Employee-related Liabilities	$ 11,657	$ 9,273
Accrued Vacation	6,047	6,583
Accrued Bonuses	7,821	750
Accrued Liabilities for Commissions, Expense and Taxes	6,687	9,845
Other Postretirement Benefits Payable	3,256	3,255
Pension and Other Postretirement and Postemployment Benefit Plans, Liabilities	273	193
Employee-related Liabilities, Current	35,741	29,899
Deferred Revenue	52,309	51,412
Self Insurance Reserve, Current	3,342	3,006
Accrued Sales Commission	8,048	9,171
Product Warranty Accrual	12,714	11,189
Accrued Liabilities	98,946	96,243
Self Insurance Reserve, Noncurrent	8,786	8,786
Other Postretirement Benefits Payable, Noncurrent	20,124	21,639
Defined Benefit Pension Plan, Liabilities, Noncurrent	7,817	9,881
Pension and Other Postretirement and Postemployment Benefit Plans, Liabilities, Noncurrent	4,529	4,486
Accrued Income Taxes, Noncurrent	1,981	1,925
Other Liabilities	5,022	5,217
Other Accrued Liabilities	22,533	21,465
Other Liabilities, Noncurrent	$ 48,259	$ 51,934