Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	$ 46,648	$ 47,271	$ 41,848
Addtitions for (reductions in) in tax positions related to current year	903	(1,624)	(3,435)
Additions for tax positions related to prior years	0	1,563	11,533
Reductions for tax positions of prior years	(27,181)	(252)	(289)
Settlements with taxing authorities	0	(310)	(319)
Lapse of statute of limitations	(740)	0	(2,067)
Balance at end of year	$ 19,630	$ 46,648	$ 47,271