Financial Instruments - Carrying Amount and Estimated Fair Values of Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, at fair value	$ 343,149	$ 324,422
Credit facilities and bank overdrafts	144	297,147
Senior Notes, Noncurrent		0
Reported Value Measurement [Member] | Senior Notes In Two Thousand Seven [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes, Noncurrent	500,000	500,000
Reported Value Measurement [Member] | Senior Notes In Two Thousand Six [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes, Noncurrent	125,000	225,000
Reported Value Measurement [Member] | Senior Notes In Two Thousand Thirteen [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes, Noncurrent	299,736
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, at fair value	343,149	324,422
Credit facilities and bank overdrafts	144	297,147
Estimate of Fair Value Measurement [Member] | Senior Notes In Two Thousand Seven [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes, Noncurrent	597,687	634,000
Estimate of Fair Value Measurement [Member] | Senior Notes In Two Thousand Six [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes, Noncurrent	140,676	248,000
Estimate of Fair Value Measurement [Member] | Senior Notes In Two Thousand Thirteen [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes, Noncurrent	$ 283,458	$ 0