Note 5 Balance Sheet Details (Property, Plant and Equipment) (Details) (USD $)	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Property, Plant and Equipment [Abstract]
Property and Plant (Useful Life of 24 Years to 50 Years)	$ 33,996,000	$ 34,190,000
Equipment Owned (Useful Life of 1 to 14 Years)	97,104,000	93,510,000
Equipment Capital Leases (Useful Life of 4 Years)	40,010,000	41,599,000
Leasehold Improvements (Useful Life of up to 8 Years)	917,000	936,000
Property, Plant and Equipment, Gross	172,027,000	170,235,000
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(120,032,000)	(114,164,000)
Property, Plant and Equipment, Net	51,995,000	56,071,000
Depreciation Expense	$ 10,200,000	$ 10,900,000	$ 11,000,000
Property and Plant [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	50 years
Property and Plant [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	24 years
Equipment Owned [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	14 years
Equipment Owned [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	1 year
Equipment Capital Leases [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	4 years
Equipment Capital Leases [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	4 years
Leasehold Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	8 years