Summary of Derivative Financial Instruments Notional Amounts on Outstanding Positions (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Foreign currency exchange forward contracts by currency:
Total notional value, net	$ 176,751	$ 143,116
Latest maturity date	Dec. 01, 2015	Dec. 01, 2015
Japanese Yen [Member]
Foreign currency exchange forward contracts by currency:
Total notional value, net	117,250	112,500
Russian Ruble [Member]
Foreign currency exchange forward contracts by currency:
Total notional value, net	4,036
South African Rand [Member]
Foreign currency exchange forward contracts by currency:
Total notional value, net	1,741
Euro [Member]
Foreign currency exchange forward contracts by currency:
Total notional value, net	4,854	5,159
Australian Dollar [Member]
Foreign currency exchange forward contracts by currency:
Total notional value, net	4,271	4,178
Mexican Peso [Member]
Foreign currency exchange forward contracts by currency:
Total notional value, net	15,007	11,400
Pound Sterling [Member]
Foreign currency exchange forward contracts by currency:
Total notional value, net	15,945	8,742
New Zealand Dollar [Member]
Foreign currency exchange forward contracts by currency:
Total notional value, net	1,756	1,137
Swedish Krona [Member]
Foreign currency exchange forward contracts by currency:
Total notional value, net	1,989
Singapore Dollar [Member]
Foreign currency exchange forward contracts by currency:
Total notional value, net	9,000
Hong Kong Dollar [Member]
Foreign currency exchange forward contracts by currency:
Total notional value, net	$ 902