Summary of Outstanding Forward Foreign Currency Contracts by Currency (Detail) In Thousands, unless otherwise specified	Mar. 31, 2015 Foreign Exchange Contracts to Sell Canadian Dollar for US Dollar USD ($)	Sep. 30, 2014 Foreign Exchange Contracts to Sell Canadian Dollar for US Dollar USD ($)	Mar. 31, 2015 Foreign Exchange Contracts to Sell Canadian Dollar for US Dollar Foreign currency forward contracts Short Not Designated as Hedging Instrument USD ($)	Mar. 31, 2015 Foreign Exchange Contracts to Sell Canadian Dollar for US Dollar Foreign currency forward contracts Short Not Designated as Hedging Instrument CAD	Sep. 30, 2014 Foreign Exchange Contracts to Sell Canadian Dollar for US Dollar Foreign currency forward contracts Short Not Designated as Hedging Instrument USD ($)	Sep. 30, 2014 Foreign Exchange Contracts to Sell Canadian Dollar for US Dollar Foreign currency forward contracts Short Not Designated as Hedging Instrument CAD	Mar. 31, 2015 Foreign Exchange Contracts To Sell European Euro for US Dollar USD ($)	Sep. 30, 2014 Foreign Exchange Contracts To Sell European Euro for US Dollar USD ($)	Mar. 31, 2015 Foreign Exchange Contracts To Sell European Euro for US Dollar Foreign currency forward contracts Short Not Designated as Hedging Instrument USD ($)	Mar. 31, 2015 Foreign Exchange Contracts To Sell European Euro for US Dollar Foreign currency forward contracts Short Not Designated as Hedging Instrument EUR (€)	Sep. 30, 2014 Foreign Exchange Contracts To Sell European Euro for US Dollar Foreign currency forward contracts Short Not Designated as Hedging Instrument USD ($)	Sep. 30, 2014 Foreign Exchange Contracts To Sell European Euro for US Dollar Foreign currency forward contracts Short Not Designated as Hedging Instrument EUR (€)	Mar. 31, 2015 Foreign Exchange Contracts To Purchase British Pounds With US Dollars USD ($)	Sep. 30, 2014 Foreign Exchange Contracts To Purchase British Pounds With US Dollars USD ($)	Mar. 31, 2015 Foreign Exchange Contracts To Purchase British Pounds With US Dollars Foreign currency forward contracts Short Not Designated as Hedging Instrument USD ($)	Mar. 31, 2015 Foreign Exchange Contracts To Purchase British Pounds With US Dollars Foreign currency forward contracts Short Not Designated as Hedging Instrument GBP (£)	Sep. 30, 2014 Foreign Exchange Contracts To Purchase British Pounds With US Dollars Foreign currency forward contracts Short Not Designated as Hedging Instrument USD ($)	Sep. 30, 2014 Foreign Exchange Contracts To Purchase British Pounds With US Dollars Foreign currency forward contracts Short Not Designated as Hedging Instrument GBP (£)
Derivative [Line Items]
Contract amount of forward foreign currency contracts			$ 5,923	7,550	$ 2,960	3,300			$ 6,508	€ 6,050	$ 4,790	€ 3,800			$ 9,400	£ 6,366	$ 11,000	£ 6,795
Fair value of forward foreign currency contracts to sell and buy foreign currency	$ 0	$ 0					$ 0	$ 0					$ 0	$ 0