Financial Instruments - Carrying Amount and Estimated Fair Values of Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, at fair value	$ 268,584	$ 405,505
Credit facilities and bank overdrafts	2,557	984
Senior Notes, Noncurrent		299,736
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	125,000
Reported Value Measurement [Member] | Senior Notes In Two Thousand Thirteen [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes, Noncurrent	299,760
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, at fair value	268,584	405,505
Credit facilities and bank overdrafts	2,557	984
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	593,909	590,024
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	137,469	139,146
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	$ 286,922	$ 278,770