Debt Facilities - Convertible Debt (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Debt Instrument [Line Items]
Long-term debt, Gross	$ 1,640,702	$ 1,243,699
Less amount representing debt discount and debt issuance cost	(15,895)	(2,681)
Long-term debt, Net	$ 5,642,849
4.75% Convertible Subordinated Notes [Member]
Debt Instrument [Line Items]
Convertible debt interest rate	4.75%		4.75%
Convertible Subordinated Debt [Member] | 4.75% Convertible Subordinated Notes [Member]
Debt Instrument [Line Items]
Long-term debt, Gross	$ 150,082	150,082
Less amount representing debt discount and debt issuance cost	(1,800)	(3,961)
Long-term debt, Net	$ 148,282	$ 146,121
Convertible debt interest rate	4.75%	4.75%