Derivative Instruments and Hedging Activities (Details 2) (Instruments designated as accounting hedges:, USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Sep. 30, 2012
Derivative instruments and hedging activities
Asset derivatives:	$ 5,164	$ 7,492
Liability derivatives:	9,868	13,337
Foreign currency forwards | Other current assets
Derivative instruments and hedging activities
Asset derivatives:	2,552	3,779
Foreign currency forwards | Other non-current assets
Derivative instruments and hedging activities
Asset derivatives:	2,612	3,713
Foreign currency forwards | Other current liabilities
Derivative instruments and hedging activities
Liability derivatives:	5,564	6,839
Foreign currency forwards | Other non-current liabilities
Derivative instruments and hedging activities
Liability derivatives:	3,831	6,407
Forward starting swap | Other non-current liabilities
Derivative instruments and hedging activities
Liability derivatives:	$ 473	$ 91