Special (Income) Charges (Details) (USD $)	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Unusual or Infrequent Item [Line Items]
Special (Income) Charges	$ 837,000	$ 1,865,000	$ 1,238,000
Other Nonrecurring Income	700,000
Severance Costs	300,000	1,900,000
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	1,000,000
Unusual or Infrequent Item [Member]
Unusual or Infrequent Item [Line Items]
Total Payment for Patent License Settlement	2,800,000		1,400,000
Patent License Expense Charged to Operations	1,500,000		1,200,000
Patent License Settlement Recorded as Prepaid Royalty	$ 1,300,000		$ 200,000