Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Sep. 30, 2018
Condensed Consolidated Balance Sheets
Allowance for accounts receivable (in dollars)	$ 4,395	$ 6,217
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	112,080,262	112,008,961
Common stock, shares outstanding	109,412,425	108,993,718
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	2,667,837	3,015,243