Annual report pursuant to Section 13 and 15(d)

LONG-TERM DEBT (Schedule of Debt Interest Expense) (Details)

v3.6.0.2
LONG-TERM DEBT (Schedule of Debt Interest Expense) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Jul. 31, 2014
May 31, 2014
2.5% Convertible Senior Notes Due 2019 [Member]          
Debt Instrument [Line Items]          
Interest rate, stated percentage 2.50%       2.50%
Contractual interest coupon $ 6,875 $ 6,856      
Amortization of debt discount 4,833 4,599      
Amortization of debt issuance costs 1,358 1,355      
Total interest cost recognized on the notes $ 13,066 $ 12,810      
2.5% Convertible Senior Notes & 2.875% Convertible Senior Notes [Member]          
Debt Instrument [Line Items]          
Contractual interest coupon     $ 8,701    
Amortization of debt discount     10,165    
Amortization of debt issuance costs     1,175    
Total interest cost recognized on the notes     $ 20,041    
2.875% Convertible Senior Notes Due 2027 [Member]          
Debt Instrument [Line Items]          
Interest rate, stated percentage     2.875% 2.875%