Annual report pursuant to Section 13 and 15(d)

SENIOR AND CONVERTIBLE SENIOR NOTES - Schedule of Senior and Convertible Senior Notes (Descriptors) (Details)

v3.6.0.2
SENIOR AND CONVERTIBLE SENIOR NOTES - Schedule of Senior and Convertible Senior Notes (Descriptors) (Details) - Senior Notes [Member] - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Jun. 02, 2015
Mar. 31, 2013
Sep. 30, 2012
Apr. 30, 2012
Dec. 31, 2010
4.50% senior notes due 2018 [Member]              
Debt Instrument [Line Items]              
Debt instrument, stated rate 4.50% 4.50%   4.50%      
7.15% senior notes due 2020 [Member]              
Debt Instrument [Line Items]              
Debt instrument, stated rate 7.15% 7.15%         7.15%
Unamortized premium $ 1,849 $ 2,418          
7.00% senior notes due 2022 [Member]              
Debt Instrument [Line Items]              
Debt instrument, stated rate 7.00% 7.00%       7.00%  
6.00% senior notes due 2025 [Member]              
Debt Instrument [Line Items]              
Debt instrument, stated rate 6.00% 6.00% 6.00%        
1.875% convertible senior notes due 2032 [Member]              
Debt Instrument [Line Items]              
Debt instrument, stated rate 1.875% 1.875%     1.875%