Borrowings - Components of Long-Term Debt (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Apr. 30, 2015	May. 21, 2014	Dec. 31, 2013	Jun. 13, 2011
Line Of Credit Facility [Line Items]
Long-term debt, Gross	$ 1,088,941	$ 1,104,598
Less: Unamortized debt discount on 3.875% Convertible Senior Subordinated Notes due 2017	(22,999)	(36,197)
Net carrying amount	1,065,942	1,068,401
Current portion of borrowings	(419,942)	(368,401)
Long-term borrowings	$ 646,000	$ 700,000
Interest rate	3.875%	3.875%			3.875%
Revolving Credit Facility
Line Of Credit Facility [Line Items]
Revolving credit facility, at a rate of 2.17% at December 31, 2015 and 1.92% at December 31, 2014, due 2018	$ 396,000	$ 200,000
Senior credit facility interest rate	2.17%	1.92%
Debt maturity date	Jul. 16, 2018
Securitization Program
Line Of Credit Facility [Line Items]
Other short-term borrowings	$ 43,300	$ 4,700
Interest rate	1.18%	0.92%
3.875% Convertible Senior Notes | Senior Notes
Line Of Credit Facility [Line Items]
3.875% Convertible Senior Subordinated Notes due 2017	$ 399,641	$ 399,898
Interest rate	3.875%	3.875%
6.875% Senior Subordinated Notes Due 2019 | Senior Notes
Line Of Credit Facility [Line Items]
6.875% Senior Subordinated Notes due 2019	$ 0	$ 250,000				$ 250,000
Interest rate	6.875%	6.875%				6.875%
5.25% Senior Subordinated Notes Due 2024 | Senior Notes
Line Of Credit Facility [Line Items]
6.875% Senior Subordinated Notes due 2019			$ 250,000
5.25% Senior Notes due 2024	$ 250,000	$ 250,000		$ 250,000
Interest rate	5.25%	5.25%	5.25%	5.25%