DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Details)
|
3 Months Ended |
6 Months Ended |
|
|
Jun. 30, 2020
USD ($)
MMcf
|
Jun. 30, 2020
USD ($)
MMcf
|
Jun. 30, 2019
USD ($)
|
Dec. 31, 2019
USD ($)
MMcf
|
| Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |
|
|
|
|
| Document Period End Date |
|
Jun. 30, 2020
|
|
|
| Derivative, Nonmonetary Notional Amount | MMcf |
14,700
|
14,700
|
|
14,300
|
| Premiums recorded in other current assets on natural gas contracts held |
$ 5,800,000
|
$ 5,800,000
|
|
$ 4,400,000
|
| Fair Value Assets, Transfers between Levels |
0
|
0
|
$ 0
|
|
| Corporate bonds in other assets |
2,900,000
|
2,900,000
|
|
2,600,000
|
| Treasury notes in other assets |
2,900,000
|
2,900,000
|
|
3,000,000.0
|
| Long-term Debt, including current maturities |
1,581,931,000
|
1,581,931,000
|
|
1,286,064,000
|
| Long-term Debt |
1,600,000,000
|
1,600,000,000
|
|
1,300,000,000
|
| Fair Value, Inputs, Level 1 [Member] |
|
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |
|
|
|
|
| Fair value, natural gas call options |
4,900,000
|
4,900,000
|
|
300,000
|
| Fair Value, Inputs, Level 2 [Member] |
|
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items] |
|
|
|
|
| Long-term Debt, Fair Value |
$ 1,900,000,000
|
$ 1,900,000,000
|
|
$ 1,500,000,000
|