Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Oct. 31, 2017	Apr. 30, 2017
Condensed Consolidated Balance Sheets
Trade accounts and notes receivable, allowances (in dollars)	$ 11,581	$ 9,851
Property and equipment, accumulated depreciation (in dollars)	$ 77,856	$ 71,409
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	41,031,000	40,971,000
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0