| Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis |
The following tables summarize the carrying amounts, fair values and fair value measurements recorded or disclosed as of December 31, 2018 and March 31, 2019 based on the three levels established by ASC 820, Fair Value Measurements and Disclosures (in thousands): | | | | | | | | | | | | | | | | | | | | | | | | December 31, 2018 | Assets (Liabilities) | | | | | | Fair Value Measurements using: | | Carrying Amount | | Fair Value | | Quoted Prices in Active Markets for Identical Assets (Level 1) | | Significant Other Observable Inputs (Level 2) | | Significant Unobservable Inputs (Level 3) | Energy commodity derivatives contracts | | $ | 55,011 |
| | $ | 55,011 |
| | $ | 55,011 |
| | $ | — |
| | $ | — |
| Interest rate contracts | | $ | (8,126 | ) | | $ | (8,126 | ) | | $ | — |
| | $ | (8,126 | ) | | $ | — |
| Long-term receivables | | $ | 20,844 |
| | $ | 20,844 |
| | $ | — |
| | $ | — |
| | $ | 20,844 |
| Guarantees | | $ | (16,409 | ) | | $ | (16,409 | ) | | $ | — |
| | $ | — |
| | $ | (16,409 | ) | Debt | | $ | (4,270,869 | ) | | $ | (4,224,373 | ) | | $ | — |
| | $ | (4,224,373 | ) | | $ | — |
|
| | | | | | | | | | | | | | | | | | | | | | | | March 31, 2019 | Assets (Liabilities) | | | | | | Fair Value Measurements using: | | Carrying Amount | | Fair Value | | Quoted Prices in Active Markets for Identical Assets (Level 1) | | Significant Other Observable Inputs (Level 2) | | Significant Unobservable Inputs (Level 3) | Energy commodity derivatives contracts | | $ | (13,272 | ) | | $ | (13,272 | ) | | $ | (13,272 | ) | | $ | — |
| | $ | — |
| Interest rate contracts | | $ | (4,474 | ) | | $ | (4,474 | ) | | $ | — |
| | $ | (4,474 | ) | | $ | — |
| Long-term receivables | | $ | 20,646 |
| | $ | 20,646 |
| | $ | — |
| | $ | — |
| | $ | 20,646 |
| Guarantees | | $ | (408 | ) | | $ | (408 | ) | | $ | — |
| | $ | — |
| | $ | (408 | ) | Debt | | $ | (4,279,676 | ) | | $ | (4,449,954 | ) | | $ | — |
| | $ | (4,449,954 | ) | | $ | — |
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