Summary of Outstanding Forward Foreign Currency Contracts by Currency (Detail) In Thousands, unless otherwise specified	Dec. 31, 2013 Foreign Exchange Contracts to Sell Canadian Dollar for US Dollar USD ($)	Sep. 30, 2013 Foreign Exchange Contracts to Sell Canadian Dollar for US Dollar USD ($)	Dec. 31, 2013 Foreign Exchange Contracts to Sell Canadian Dollar for US Dollar Foreign currency forward contracts Short Not Designated as Hedging Instrument USD ($)	Dec. 31, 2013 Foreign Exchange Contracts to Sell Canadian Dollar for US Dollar Foreign currency forward contracts Short Not Designated as Hedging Instrument CAD	Sep. 30, 2013 Foreign Exchange Contracts to Sell Canadian Dollar for US Dollar Foreign currency forward contracts Short Not Designated as Hedging Instrument USD ($)	Sep. 30, 2013 Foreign Exchange Contracts to Sell Canadian Dollar for US Dollar Foreign currency forward contracts Short Not Designated as Hedging Instrument CAD	Dec. 31, 2013 Foreign Exchange Contracts To Sell European Euro for US Dollar USD ($)	Sep. 30, 2013 Foreign Exchange Contracts To Sell European Euro for US Dollar USD ($)	Dec. 31, 2013 Foreign Exchange Contracts To Sell European Euro for US Dollar Foreign currency forward contracts Short Not Designated as Hedging Instrument USD ($)	Dec. 31, 2013 Foreign Exchange Contracts To Sell European Euro for US Dollar Foreign currency forward contracts Short Not Designated as Hedging Instrument EUR (€)	Sep. 30, 2013 Foreign Exchange Contracts To Sell European Euro for US Dollar Foreign currency forward contracts Short Not Designated as Hedging Instrument USD ($)	Sep. 30, 2013 Foreign Exchange Contracts To Sell European Euro for US Dollar Foreign currency forward contracts Short Not Designated as Hedging Instrument EUR (€)	Dec. 31, 2013 Foreign Exchange Contracts To Purchase British Pounds With US Dollars USD ($)	Sep. 30, 2013 Foreign Exchange Contracts To Purchase British Pounds With US Dollars USD ($)	Dec. 31, 2013 Foreign Exchange Contracts To Purchase British Pounds With US Dollars Foreign currency forward contracts Short Not Designated as Hedging Instrument USD ($)	Dec. 31, 2013 Foreign Exchange Contracts To Purchase British Pounds With US Dollars Foreign currency forward contracts Short Not Designated as Hedging Instrument GBP (£)	Sep. 30, 2013 Foreign Exchange Contracts To Purchase British Pounds With US Dollars Foreign currency forward contracts Short Not Designated as Hedging Instrument USD ($)	Sep. 30, 2013 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			$ 4,398	4,700	$ 4,542	4,700			$ 7,818	€ 5,700	$ 7,307	€ 5,400			$ 6,000	£ 3,633	$ 10,500	£ 6,513
Fair value of forward foreign currency contracts to sell and buy foreign currency