Components of Long-Term Debt (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Jun. 13, 2011
Line Of Credit Facility [Line Items]
Long-term debt, Gross	$ 1,330,000	$ 1,025,000
Less: Unamortized debt discount on 3.875% Convertible Senior Subordinated Notes	(48,413)	(59,720)
Total long-term debt	1,281,587	965,280
Current portion of borrowings	(351,587)
Total long-term debt	930,000	965,280
Revolving Credit Facility
Line Of Credit Facility [Line Items]
Senior Credit Facility	680,000
Term loan facility, at a rate of 2.75%
Line Of Credit Facility [Line Items]
Senior Credit Facility		375,000
3.875% Convertible Senior Subordinated Notes
Line Of Credit Facility [Line Items]
3.875% Convertible Senior Subordinated Notes	400,000	400,000
6.875% Senior Subordinated Notes Due 2019
Line Of Credit Facility [Line Items]
6.875% Senior Subordinated Notes due 2019	$ 250,000	$ 250,000	$ 250,000