Credit Facilities, Short-term Borrowings and Long-term Debt (Narrative) (Details) € in Thousands, BRL in Thousands, $ in Thousands		3 Months Ended		12 Months Ended
	Jan. 23, 2017 BRL	Dec. 31, 2016 USD ($)	Dec. 31, 2015	Sep. 30, 2016 USD ($)	Dec. 31, 2016 BRL	Dec. 31, 2016 EUR (€)	Dec. 31, 2016 USD ($)
Short-term borrowings				$ 150,000			$ 150,000
Balance of unamortized debt issuance costs				$ 2,091			1,974
Other Foreign Short-term Borrowings [Member]
Outstanding borrowings							0
Revolving Credit Agreement [Member]
Maximum borrowing capacity							1,000,000
Option to increase maximum borrowings to this amount							$ 1,200,000
Line of Credit Facility, Expiration Date		Apr. 01, 2020
Variable Rate Basis		LIBOR
Credit facility effective interest rate on outstanding borrowing				1.77%	1.66%	1.66%	1.66%
Outstanding borrowings				$ 156,700			$ 160,550
Current portion of outstanding borrowings		$ 150,000		150,000
Balance of unamortized debt issuance costs, line of credit				3,134			2,915
Chinese Credit Facility [Member]
Maximum borrowing capacity				$ 22,700			22,700
Outstanding borrowings							0
Chinese Credit Facility, RMB Denominated Loan [Member]
Variable Rate Basis		prevailing interest rate offered by the People's Bank of China on the date of borrowing, plus a margin equal to 15% of that prevailing rate		interest at the prevailing interest rate offered by the People's Bank of China on the date of borrowing, plus a margin equal to 15% of that prevailing rate
Chinese Credit Facility, USD Denominated Loan [Member]
Variable Rate Basis		lender's cost of borrowing rate at the date of borrowing, plus 3%		interest at the lender's cost of borrowing rate at the date of borrowing, plus 3%
Brazil Credit Facility BRL Denominated Loan [Member]
Maximum borrowing capacity | BRL	BRL 1,000				BRL 52,000
Line of Credit Facility, Expiration Date	Jul. 14, 2017
Variable Rate Basis				interest at the lender's cost of borrowing rate at the date of borrowing, plus 1.75%
Basis Spread On Variable Rate		1.75%
Outstanding borrowings							0
Minimum [Member] | Revolving Credit Agreement [Member]
Basis Spread On Variable Rate		0.85%
Maximum [Member] | Revolving Credit Agreement [Member]
Basis Spread On Variable Rate		1.65%
The Notes [Member]
Balance of unamortized debt issuance costs				$ 2,091			1,974
2008 Note Purchase Agreement [Member]
Issuance Date		Oct. 01, 2008
2009 Note Purchase Agreement [Member]
Issuance Date		Apr. 01, 2009
2013 Note Purchase Agreement [Member]
Issuance Date		Oct. 01, 2013
Face Amount							$ 250,000
First Closing Notes [Member]
Issuance Date		Oct. 01, 2013
Second Closing Notes [Member]
Issuance Date		Nov. 15, 2013	Nov. 15, 2013
Series J Notes [Member]
Variable interest rate					2.16%	2.16%	2.16%
2016 Note Purchase Agreements [Member]
Issuance Date		Sep. 23, 2016
Face Amount | €						€ 160,000
Series M Notes [Member]
Face Amount | €						40,000
Series N Notes [Member]
Face Amount | €						77,000
Series O Notes [Member]
Face Amount | €						€ 43,000