Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.2
FAIR VALUE MEASUREMENTS (Fair Value of Debt) (Details) - Level 2 [Member] - USD ($)
$ in Thousands
Jun. 30, 2019
Dec. 31, 2018
4.875% Senior Notes Due 2024 [Member]    
Debt Fair Value [Line Items]    
Estimated fair values of senior notes $ 592,204 $ 552,368
5.625% Senior Notes Due 2026 [Member]    
Debt Fair Value [Line Items]    
Estimated fair values of senior notes 315,129 302,097
5.375% Senior Notes due 2022 [Member]    
Debt Fair Value [Line Items]    
Estimated fair values of senior notes 254,243 251,390
2.5% Convertible Senior Notes Due 2023 [Member]    
Debt Fair Value [Line Items]    
Estimated fair values of convertible senior notes 652,141 561,699
2.5% Convertible Senior Notes Due 2019 [Member]    
Debt Fair Value [Line Items]    
Estimated fair values of convertible senior notes $ 0 $ 40,710