Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Consolidated Balance Sheets
Allowance for accounts receivable (in dollars)	$ 6,217	$ 5,721
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized	160,000,000	160,000,000
Common stock, shares issued	112,008,961	111,956,875
Common stock, shares outstanding	108,993,718	108,604,047
Preferred stock, no par value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Treasury stock, shares	3,015,243	3,352,828