Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	May. 31, 2015	May. 31, 2014
Allowance for doubtful accounts	$ 604	$ 555
Accumulated depreciation on rental and lease equipment	241,116	237,151
Accumulated depreciation and amortization for other property	16,749	18,983
Amortization of intangibles	$ 1,761	$ 1,632
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued
Common stock, par value
Commons stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	24,108,176	24,007,709
Common stock, shares outstanding	24,108,176	24,007,709