CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2013	Sep. 30, 2012
Current assets
Allowance for doubtful accounts	$ 4,061	$ 4,757
Stockholders' equity
Common stock: Authorized	200,000,000	200,000,000
Common stock: par value	$ 0.001	$ 0.001
Common stock: Issued	29,590,023	28,864,527
Treasury stock at cost, shares	6,319,094	5,682,288