Forward Contracts with Notional Values (Detail) (Forward Contracts) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 Indian Rupees INR	Dec. 31, 2013 Indian Rupees INR	Dec. 31, 2014 Australian Dollar AUD	Dec. 31, 2013 Australian Dollar AUD	Dec. 31, 2014 British pound GBP (£)	Dec. 31, 2013 British pound GBP (£)	Dec. 31, 2012 British pound GBP (£)	Dec. 31, 2014 Euro EUR (€)	Dec. 31, 2013 Euro EUR (€)	Dec. 31, 2012 Euro EUR (€)
Derivative [Line Items]
Notional amount	204,000	690,000	12,900	26,300	£ 26,500	£ 85,400	£ 52,000	€ 21,900	€ 102,300	€ 49,700