CONSOLIDATED BALANCE SHEET (Parenthetical) (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2017	Sep. 30, 2016
Statement Of Financial Position [Abstract]
Accounts receivable, allowances	$ 17,956	$ 17,028
Common stock, par value	$ 0.20	$ 0.20
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares issued	33,096,743	32,564,252
Treasury stock, shares repurchased	3,135,927	3,135,927