Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Aug. 31, 2014	May 31, 2014
Receivables, allowance	$ 4,854	$ 4,784
Intangible assets, accumulated amortization	$ 13,585	$ 12,698
Preferred stock, shares authorized	500,000	500,000
Preferred stock, shares issued
Common stock, par value	$ 0.30	$ 0.30
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares issued	20,573,288	20,477,938