Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	May 31, 2016	May 31, 2015
Allowance for doubtful accounts	$ 464	$ 604
Accumulated depreciation on rental and lease equipment	235,387	241,116
Accumulated depreciation and amortization for other property	17,653	16,749
Amortization of intangibles	$ 1,879	$ 1,761
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	24,196,634	24,108,176
Common stock, shares outstanding	24,196,634	24,108,176