LONG-TERM DEBT - Schedule of Long-term Debt, Net of Discounts (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Oct. 22, 2014
Debt Instrument [Line Items]
Unamortized discount on convertible senior notes	$ (12,877)	$ (15,932)
Unamortized debt issuance costs	(3,874)	(4,977)
Long-term debt	183,291	194,272
Less: current portion of long-term debt, net	10,800	9,773
Long-term debt, net, less current portion	$ 172,491	$ 184,499
3.50% Convertible Senior Notes Due 2019
Debt Instrument [Line Items]
Interest rate	3.50%	3.50%
Convertible Debt | 3.50% Convertible Senior Notes Due 2019
Debt Instrument [Line Items]
Long-term debt	$ 133,750	$ 143,750
Interest rate	3.50%		3.50%	3.50%
Revolving Credit Facility
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ (1,019)
Less: current portion of long-term debt, net	$ 11,819
Revolving Credit Facility | Term Loan Facility
Debt Instrument [Line Items]
Long-term debt		$ 71,431