Derivative Instruments and Hedging Activities - Fair value of derivative financial instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Sep. 30, 2015
Derivative Instruments and Hedging Activities
Asset derivatives:	$ 15,296	$ 25,230
Liability derivatives:	13,838	23,279
Foreign currency forwards | Other current assets
Derivative Instruments and Hedging Activities
Asset derivatives:	14,568	11,321
Foreign currency forwards | Other noncurrent assets
Derivative Instruments and Hedging Activities
Asset derivatives:	728	13,909
Foreign currency forwards | Other current liabilities
Derivative Instruments and Hedging Activities
Liability derivatives:	13,445	9,370
Foreign currency forwards | Other noncurrent liabilities
Derivative Instruments and Hedging Activities
Liability derivatives:	$ 393	$ 13,909