Consolidated Condensed Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Feb. 28, 2013	May 31, 2012
Receivables, allowance	$ 5,352	$ 4,405
Intangible assets, accumulated amortization	$ 8,118	$ 5,658
Preferred stock, shares authorized	500,000	500,000
Preferred stock, shares issued
Common stock, par value	$ 0.30	$ 0.30
Common stock, shares authorized	30,000,000	30,000,000
Common stock, shares issued	20,586,397	19,954,996
Treasury stock at cost, shares	89,569	89,569