Condensed Consolidated Statements Of Comprehensive Income (Loss) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 31, 2012	Oct. 31, 2011	Oct. 31, 2012	Oct. 31, 2011
Statement of Other Comprehensive Income [Abstract]
Net loss	$ 1,950	$ (2,976)	$ 2,511	$ (5,692)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Change in pension benefits	141	331	282	662
Total Comprehensive Income (Loss)	$ 2,091	$ (2,645)	$ 2,793	$ (5,030)