Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Nov. 30, 2011	May 31, 2011
ASSETS
Allowance for doubtful accounts	$ 542	$ 602
Accumulated depreciation on rental and lease equipment	194,420	191,160
Accumulated depreciation and amortization for other property	17,315	16,825
Amortization of intangibles	$ 1,221	$ 1,151
Shareholders' equity:
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued
Preferred stock, shares outstanding
Common stock, par value
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	23,980,581	23,980,581
Common stock, shares outstanding	23,980,581	23,980,581