Financial Instruments (Narrative) (Details) $ in Thousands	May 11, 2017 USD ($)	Oct. 01, 2017 USD ($) Forward_Contracts	Dec. 31, 2016 USD ($) Forward_Contracts
Derivative [Line Items]
Letters of Credit Outstanding, Amount		$ 40,433
Number of Foreign Currency Derivatives Held | Forward_Contracts		0	4
Forward Contracts [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability			$ 100
Downstream [Member]
Derivative [Line Items]
Contingent Consideration Classified as Equity, Fair Value Disclosure		$ 0	$ 12,200
New Credit Agreement [Member]
Derivative [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 400,000
Long-term Debt	$ 100,000	$ 269,000
Debt Instrument, Periodic Payment, Percentage of Principal	1.125%
Debt Instrument, Annual Principal Payment	$ 5,000
Debt Instrument, Periodic Payment, Principal	1,300
Prior Credit Agreement [Member]
Derivative [Line Items]
Extinguishment of Debt, Amount	$ 254,000