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LONG-TERM DEBT (Summary of Long-Term Debt) (Details) - USD ($) $ in Thousands | Mar. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Debt Instrument [Line Items] |  |
Total Debt | $ 2,282,811 | $ 2,258,962
Less: current maturities of long-term debt | (279,807) | (253,743)
Less: amounts reclassified to liabilities subject to compromise | (2,003,004) | (2,005,219)
Total Debt reflected as long term | 0 | 0
6.625% senior unsecured notes due 2023 | Senior Notes |  |
Debt Instrument [Line Items] |  |
Long-term debt | $ 324,583 | 324,583
Stated interest rate | 6.625% |
6.000% senior unsecured notes due 2024 | Senior Notes |  |
Debt Instrument [Line Items] |  |
Long-term debt | $ 579,568 | 579,568
Stated interest rate | 6.00% |
6.375% senior unsecured notes due 2025 | Senior Notes |  |
Debt Instrument [Line Items] |  |
Long-term debt | $ 507,870 | 507,870
Stated interest rate | 6.375% |
6.375% senior unsecured notes due 2026 | Senior Notes |  |
Debt Instrument [Line Items] |  |
Long-term debt | $ 374,617 | 374,617
Stated interest rate | 6.375% |
Building loan |  |
Debt Instrument [Line Items] |  |
Long-term debt | $ 21,914 | 21,914
Revolving Credit Agreement | DIP credit facility |  |
Debt Instrument [Line Items] |  |
Long-term debt | 157,500 | 157,500
Revolving Credit Agreement | Pre-petition revolving credit facility |  |
Debt Instrument [Line Items] |  |
Long-term debt | $ 316,759 | $ 292,910

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