Annual report pursuant to Section 13 and 15(d)

FAIR VALUE MEASUREMENTS (Fair Value of Debt) (Details)

v3.20.4
FAIR VALUE MEASUREMENTS (Fair Value of Debt) (Details) - Fair Value, Inputs, Level 2 [Member] - USD ($)
$ in Thousands
Dec. 31, 2020
Dec. 31, 2019
6.5% Senior Secured Notes Due 2027 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term Debt, Fair Value $ 1,340,688 $ 0
4.75% Senior Notes Due 2027 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term Debt, Fair Value 970,872 983,735
4.875% Senior Notes Due 2024 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term Debt, Fair Value 581,480 596,137
5.625% Senior Notes Due 2026 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term Debt, Fair Value 307,785 320,553
2.5% Convertible Senior Notes Due 2023 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Convertible Debt, Fair Value Disclosures 720,764 675,664
2.0% Convertible Senior Notes due 2025 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Convertible Debt, Fair Value Disclosures $ 425,172 $ 0