Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Apr. 30, 2018	Apr. 30, 2017
Condensed Consolidated Balance Sheets
Trade accounts and notes receivable, allowances (in dollars)	$ 9,633	$ 9,851
Property and equipment, accumulated depreciation (in dollars)	$ 85,761	$ 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	41,069,000	40,971,000
Common stock, shares outstanding	41,069,000	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
Preferred stock, shares outstanding	0	0