Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Sep. 30, 2020
Current Assets
Allowance for accounts receivable	$ 1,806	$ 1,820
Common Stock
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized (in shares)	160,000,000	160,000,000
Common stock, shares issued (in shares)	112,222,865	112,151,563
Common stock, shares outstanding (in shares)	107,893,998	107,488,242
Preferred Stock
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares issued (in shares)	0	0
Treasury Stock
Treasury stock, shares (in shares)	4,328,867	4,663,321