CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Apr. 30, 2014	Apr. 30, 2013
Statement Of Financial Position [Abstract]
Allowance for receivables	$ 229	$ 194
Common stock, par value	$ 2.50	$ 2.50
Common stock, shares authorized	5,000	5,000
Common stock, shares issued	2,623	2,623
Common stock, shares outstanding	2,619	2,592
Treasury stock, shares	4	27