EMPLOYEE BENEFIT PLANS Table 2 - Components of Net Periodic Benefit Cost (Income) (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Defined Benefit Plan Disclosure [Line Items] | |||
| Defined benefit plan, assumptions used in calculations description | We amortize prior service costs and credits on a straight-line basis over the average remaining service period of employees expected to receive benefits under our Pension Plans and other postretirement benefit plans (“Amortization of prior service credit” in table above). We amortize the actuarial gains and losses that exceed 10% of the greater of the projected benefit obligation or market-related value of plan assets (smoothed asset value) over the average remaining service period of active employees expected to receive benefits under our Pension Plans and other postretirement benefit plans (“Amortization of net actuarial loss” in table above). | ||
| Pension Plan [Member] | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Service cost | $ 9,549 | $ 9,621 | $ 8,955 |
| Interest cost | 5,480 | 4,824 | 4,507 |
| Expected return on plan assets | (8,015) | (7,417) | (6,411) |
| Amortization of prior service credit | (2,057) | (2,057) | (2,059) |
| Amortization of net actuarial loss | 846 | 2,174 | 1,484 |
| Net periodic benefit cost (income) | 5,803 | 7,145 | 6,476 |
| Other Postretirement Benefit Plans [Member] | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Service cost | 431 | 504 | 456 |
| Interest cost | 453 | 429 | 430 |
| Expected return on plan assets | 0 | 0 | 0 |
| Amortization of prior service credit | (1,145) | (1,145) | (1,145) |
| Amortization of net actuarial loss | 42 | 214 | 191 |
| Net periodic benefit cost (income) | $ (219) | $ 2 | $ (68) |