Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012	Sep. 30, 2011
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 3,313	$ 3,902
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	119,487,000	116,937,000
Common stock, shares outstanding	119,487,000	116,937,000