Financial Instruments - Carrying Amount and Estimated Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands		Jun. 30, 2015	Dec. 31, 2014
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, at fair value	[1]	$ 377,254	$ 478,573
Credit facilities and bank overdrafts	[2]	68,948	12,335
Senior Notes, Noncurrent	[3]		299,782
Reported Value Measurement [Member] | Senior Notes 2007 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes, Noncurrent	[3]	500,000	500,000
Reported Value Measurement [Member] | Senior Notes 2006 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes, Noncurrent	[3]	125,000	125,000
Reported Value Measurement [Member] | Senior Notes 2013 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes, Noncurrent	[3]	299,795
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, at fair value	[1]	377,254	478,573
Credit facilities and bank overdrafts	[2]	68,948	12,335
Estimate of Fair Value Measurement [Member] | Senior Notes 2007 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes, Noncurrent	[3]	576,942	587,650
Estimate of Fair Value Measurement [Member] | Senior Notes 2006 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes, Noncurrent	[3]	130,352	133,137
Estimate of Fair Value Measurement [Member] | Senior Notes 2013 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Senior Notes, Noncurrent	[3]	$ 294,136	$ 296,290

[1] The carrying amount of cash and cash equivalents approximates fair value due to the short maturity of those instruments.

[2] The carrying amount of our credit facilities and bank overdrafts approximates fair value as the interest rate is reset frequently based on current market rates as well as the short maturity of those instruments.

[3] The fair value of our long-term debt was calculated using discounted cash flows applying current interest rates and current credit spreads based on our own credit risk.