Product Warranty (Schedule Of Warranty Liability) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Jan. 31, 2013	Jan. 31, 2012
Product Warranty [Abstract]
Beginning balance at May 1	$ 1,885	$ 1,738
Accrual	6,959	6,337
Settlements	(7,168)	(6,384)
Ending balance at October 31	$ 1,676	$ 1,691