Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Jan. 31, 2018	Apr. 30, 2017
Condensed Consolidated Balance Sheets
Trade accounts and notes receivable, allowances (in dollars)	$ 10,665	$ 9,851
Property and equipment, accumulated depreciation (in dollars)	$ 81,648	$ 71,409
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	500,000	500,000
Common stock, shares issued	41,041	40,971
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000	50,000
Preferred stock, shares issued	0	0