Income Taxes (Details 5) (USD $)	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Income Taxes
Gross unrecognized income tax benefits at beginning of year	$ 8,312,000	$ 11,843,000	$ 9,024,000
Changes based on tax positions related to the current year	(370,000)	(872,000)	93,000
Increases for tax positions related to prior years	560,000	4,915,000	4,961,000
Reductions for tax positions related to prior years	(2,073,000)	(5,365,000)	(1,444,000)
Settlements	(65,000)	(1,720,000)	(592,000)
Lapse of statute of limitations	(1,492,000)	(489,000)	(199,000)
Gross unrecognized income tax benefits at end of year	4,872,000	8,312,000	11,843,000
Income tax
Unrecognized tax benefits that would impact effective tax rate	3,900,000
Recognized interest and penalties			200,000
Released liabilities for interest and penalties	400,000	3,400,000
Interest and penalties accrued	2,400,000
Tax audit by IRS year under examination	2009
Minimum
Income tax
Reasonably possible unrecognized income tax benefits released within next 12 months	1,500,000
Maximum
Income tax
Reasonably possible unrecognized income tax benefits released within next 12 months	$ 3,000,000