Derivative Instruments and Hedging Activities Open Foreign Currency Contracts (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Net Unrealized Gain (Loss)	$ (8,791)	$ 2,599
Cash Flow Hedging | Foreign Exchange Contract
Derivative [Line Items]
Notional Amounts (in U.S. Dollars)	216,466
Net Unrealized Gain (Loss)	(8,791)
Cash Flow Hedging | Foreign Exchange Contract | Australian Dollar
Derivative [Line Items]
Notional Amounts (in U.S. Dollars)	25,522
Net Unrealized Gain (Loss)	(260)
Cash Flow Hedging | Foreign Exchange Contract | Canadian Dollar
Derivative [Line Items]
Notional Amounts (in U.S. Dollars)	160,247
Net Unrealized Gain (Loss)	(7,090)
Cash Flow Hedging | Foreign Exchange Contract | Japanese Yen
Derivative [Line Items]
Notional Amounts (in U.S. Dollars)	1,417
Net Unrealized Gain (Loss)	210
Cash Flow Hedging | Foreign Exchange Contract | Mexican Peso
Derivative [Line Items]
Notional Amounts (in U.S. Dollars)	29,280
Net Unrealized Gain (Loss)	$ (1,651)