Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Sep. 30, 2014
Liabilities
Long-term debt (c)	$ 1,809,400	$ 1,811,600
Unamortized debt issuance costs	21,800	25,700
Fair value measurement on recurring basis | Total
Assets
Cash equivalents (a)	46,003	27,000
Total assets	46,325	27,511
Liabilities
Long-term debt (c)	1,873,620	1,874,444
Total liabilities	1,873,678	1,874,491
Fair value measurement on recurring basis | Foreign exchange contracts | Total
Assets
Foreign exchange contracts (b)	322	511
Liabilities
Foreign exchange contracts (b)	58	47
Fair value measurement on recurring basis | Level 1
Assets
Cash equivalents (a)	46,003	27,000
Total assets	46,003	27,000
Liabilities
Long-term debt (c)	1,870,750	1,870,250
Total liabilities	1,870,750	1,870,250
Fair value measurement on recurring basis | Level 2
Assets
Total assets	322	511
Liabilities
Long-term debt (c)	2,870	4,194
Total liabilities	2,928	4,241
Fair value measurement on recurring basis | Level 2 | Foreign exchange contracts
Assets
Foreign exchange contracts (b)	322	511
Liabilities
Foreign exchange contracts (b)	$ 58	$ 47