Additional Consolidated Balance Sheets Information Level 4 (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Mar. 31, 2012
Employee-related Liabilities	$ 13,162	$ 9,273
Accrued Vacation	6,045	6,583
Accrued Bonuses	4,927	750
Accrued Liabilities for Commissions, Expense and Taxes	5,399	9,845
Other Postretirement Benefits Payable	3,255	3,255
Pension and Other Postretirement and Postemployment Benefit Plans, Liabilities	297	193
Employee-related Liabilities, Current	33,085	29,899
Deferred Revenue	53,220	51,412
Self Insurance Reserve, Current	3,266	3,006
Accrued Sales Commission	8,677	9,171
Product Warranty Accrual	12,616	11,189
Accrued Liabilities	97,703	96,243
Self Insurance Reserve, Noncurrent	8,786	8,786
Other Postretirement Benefits Payable, Noncurrent	20,841	21,639
Defined Benefit Pension Plan, Liabilities, Noncurrent	8,925	9,881
Pension and Other Postretirement and Postemployment Benefit Plans, Liabilities, Noncurrent	4,196	4,486
Accrued Income Taxes, Noncurrent	1,983	1,925
Other Liabilities	4,990	5,217
Other Accrued Liabilities	19,924	21,465
Other Liabilities, Noncurrent	$ 49,721	$ 51,934