Goodwill And Intangible Assets (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2012
Goodwill And Intangible Assets [Abstract]
Intangible assets amortization expense	$ 400	$ 500	$ 1,154	$ 1,632