Income Taxes (Details 6) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010 Predecessor
Changes in gross unrecognized tax benefits
Beginning balance	$ 10,687	$ 9,210	$ 9,229
Increases related to prior year tax positions	888	2,207	1,252
Increase based on tax positions related to the current year	1,313
Decreases related to settlements with taxing authorities			(669)
Decreases related to lapsing of statute of limitations		(730)	(602)
Balance at the end of the period	12,888	10,687	9,210
Unrecognized tax benefits, other disclosures
Total unrecognized tax benefits that, if recognized, would affect effective tax rate	10,160	8,195
Accrued interest	1,385
Accrued penalties	$ 700

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