Derivative Instruments and Hedging Activities Open Foreign Currency Contracts (Details) - Cash Flow Hedging - Foreign Exchange Contract - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Notional Amounts (in U.S. Dollars)	$ 189,576	$ 74,355
Net Unrealized Gain (Loss)	602	3,128
Australian Dollar
Derivative [Line Items]
Notional Amounts (in U.S. Dollars)	20,217	0
Net Unrealized Gain (Loss)	156	0
Canadian Dollar
Derivative [Line Items]
Notional Amounts (in U.S. Dollars)	151,769	55,133
Net Unrealized Gain (Loss)	(596)	2,564
Mexican Peso
Derivative [Line Items]
Notional Amounts (in U.S. Dollars)	17,590	19,222
Net Unrealized Gain (Loss)	$ 1,042	$ 564