Long-Term Debt (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Sep. 30, 2011
Long term debt
Long term debt	$ 761,785	$ 760,042
Less current portion	8,800	5,300
Long term debt, noncurrent	752,985	754,742
Term loan, principal and interest due in quarterly installments through February 9, 2017 [Member]
Long term debt
Long term debt	523,375	527,350
Original issue discount on term loan, net of accumulated amortization [Member]
Long term debt
Original issue discount and initial purchase discount on senior notes, net of accumulated amortization	(6,072)	(7,081)
Senior notes [Member]
Long term debt
Long term debt	250,000	250,000
Original issue discount and initial purchase discount on senior notes, net of accumulated amortization [Member]
Long term debt
Original issue discount and initial purchase discount on senior notes, net of accumulated amortization	(9,018)	(10,227)
Senior revolver, due February 9, 2016; quarterly cash interest payments at a variable interest rate [Member]
Long term debt
Long term debt	$ 3,500