Derivative Instruments and Hedging Activities - Open Foreign Currency Contracts (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Derivative [Line Items]
Derivative, Fair Value, Net	$ 1,964	$ (2,741)
Cash Flow Hedging | Foreign exchange contracts
Derivative [Line Items]
Notional Amounts (in US Dollars)	123,976
Derivative, Fair Value, Net	2,219
Cash Flow Hedging | Foreign exchange contracts | Currency, Australian Dollar
Derivative [Line Items]
Notional Amounts (in US Dollars)	7,531
Derivative, Fair Value, Net	809
Cash Flow Hedging | Foreign exchange contracts | Currency, Canadian Dollar
Derivative [Line Items]
Notional Amounts (in US Dollars)	67,570
Derivative, Fair Value, Net	1,845
Cash Flow Hedging | Foreign exchange contracts | Currency, Japanese Yen
Derivative [Line Items]
Notional Amounts (in US Dollars)	26,925
Derivative, Fair Value, Net	(1,002)
Cash Flow Hedging | Foreign exchange contracts | Currency, Mexican Peso
Derivative [Line Items]
Notional Amounts (in US Dollars)	8,999
Derivative, Fair Value, Net	120
Cash Flow Hedging | Foreign exchange contracts | Norwegian Kroner
Derivative [Line Items]
Notional Amounts (in US Dollars)	4,848
Derivative, Fair Value, Net	227
Cash Flow Hedging | Foreign exchange contracts | Currency, Swedish Krone
Derivative [Line Items]
Notional Amounts (in US Dollars)	8,103
Derivative, Fair Value, Net	$ 220