Debt (Details) (USD $) In Thousands, unless otherwise specified					3 Months Ended			3 Months Ended			3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 US Dollar Amounts [Member]	Mar. 31, 2014 Other Principal Trading Currencies [Member]	Mar. 31, 2014 6.3% Senior Notes [Member]	Mar. 31, 2014 6.3% Senior Notes [Member] US Dollar Amounts [Member]	Mar. 31, 2014 6.3% Senior Notes [Member] Other Principal Trading Currencies [Member]	Mar. 31, 2014 3.67 Percent Senior Notes [Member]	Mar. 31, 2014 3.67 Percent Senior Notes [Member] US Dollar Amounts [Member]	Mar. 31, 2014 3.67 Percent Senior Notes [Member] Other Principal Trading Currencies [Member]	Mar. 31, 2014 4.10% Senior Notes [Member]	Mar. 31, 2014 4.10% Senior Notes [Member] US Dollar Amounts [Member]	Mar. 31, 2014 4.10% Senior Notes [Member] Other Principal Trading Currencies [Member]	Mar. 31, 2014 $ 800 Million Credit Agreement [Member]	Mar. 31, 2014 $ 800 Million Credit Agreement [Member] US Dollar Amounts [Member]	Mar. 31, 2014 $ 800 Million Credit Agreement [Member] Other Principal Trading Currencies [Member]	Mar. 31, 2014 Other Local Arrangements [Member]	Mar. 31, 2014 Other Local Arrangements [Member] US Dollar Amounts [Member]	Mar. 31, 2014 Other Local Arrangements [Member] Other Principal Trading Currencies [Member]
Debt Instrument [Line Items]
Senior Notes					$ 100,000	$ 100,000	$ 0	$ 50,000	$ 50,000	$ 0	$ 50,000	$ 50,000	$ 0
Line of Credit Facility, Amount Outstanding														249,582	231,584	17,998
Other Borrowings																	16,255	0	16,255
Long-Term Debt, by Current and Noncurrent, and Short-Term Debt
Total debt	465,837		431,584	34,253
Less: current portion	(16,255)	(17,067)	0	(16,255)
Long-Term Debt
Long-term debt	449,582	395,960	431,584	17,998
Debt Instrument, Face Amount					100,000			50,000			50,000
Debt Instrument, Maturity Date					Jun. 25, 2015			Dec. 17, 2022			Sep. 19, 2023
Debt Instrument, Interest Rate, Stated Percentage					6.30%			3.67%			4.10%
Line of Credit Facility, Remaining Borrowing Capacity														$ 546,400