Long-Term Debt (Details) (USD $) In Thousands, unless otherwise specified			12 Months Ended			12 Months Ended			12 Months Ended			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 4.75% Senior Notes	Dec. 31, 2011 4.75% Senior Notes	Nov. 30, 2009 4.75% Senior Notes	Dec. 31, 2012 4.00% Senior Notes	Jan. 31, 2012 4.00% Senior Notes	Dec. 31, 2011 4.00% Senior Notes	Dec. 31, 2012 Revolving Credit Facility	Dec. 31, 2011 Revolving Credit Facility	Jun. 30, 2011 Revolving Credit Facility	Dec. 31, 2012 Receivables Securitization Facility	Dec. 31, 2011 Receivables Securitization Facility	Dec. 31, 2010 Receivables Securitization Facility	Dec. 31, 2012 Notes payable to foreign banks and other debt	Dec. 31, 2011 Notes payable to foreign banks and other debt
Debt
Debt	$ 1,706,497	$ 1,377,129	$ 599,589	$ 599,365		$ 498,846			$ 500,400	$ 692,400		$ 100,000	$ 81,700		$ 7,662	$ 3,664
Less current portion	100,293	298
Total long-term debt	1,606,204	1,376,831
Average Interest Rate (as a percent)			4.75%	4.75%		4.00%			1.52%	1.55%		0.86%	2.14%		8.45%	6.23%
Unamortized discount			411	635		1,154
Commitment under the Revolving Credit Facility											1,000,000
Borrowings under the Revolving Credit Facility									500,400
Availability under the Revolving Credit Facility									499,600
Interest rate on borrowings under the Revolving Credit Facility, variable rate									LIBOR
Debt instrument, principal amount					600,000		500,000
Stated interest rate (as a percent)			4.75%		4.75%	4.00%	4.00%
Debt instrument, face amount, net of discount (as a percent)					99.813%		99.746%
Redemption price as a percentage of principal amount (as a percent)						100.00%
Debt instrument, fair value			640,000	643,000		533,000
Maximum amount of undivided interest												100,000
Fees payable under credit facility												1,000	1,600	1,500
Maturity of the Company's long-term debt over each of the next five years
2013	100,293
2014	600,404
2015	94
2016	500,708
2017	6,152
Thereafter	498,846
Long-term debt including current portion	1,706,497	1,377,129	599,589	599,365		498,846			500,400	692,400		100,000	81,700		7,662	3,664
Unused letters of credit	$ 14,600