CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Sep. 30, 2021
Current assets:
Accounts receivable, allowances for doubtful accounts	$ 9,536	$ 10,073
Stockholders’ equity:
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	560,000,000	560,000,000
Common stock, shares issued (in shares)	322,582,000	319,402,000
Common stock, shares outstanding (in shares)	318,831,000	315,651,000
Treasury stock, shares (in shares)	3,751,000	3,751,000