BENEFIT PLANS (Fair Values of Pension Plan Assets) (Details) - Pension Plans, Defined Benefit [Member] - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	$ 435,692	$ 168,953
Commodity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets		14,697
Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	120,802	135,902
Investments In The Fair Value Hierarchy [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	556,494	319,552
Interest In Common/Collective Trusts [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	387,785	462,566
Private Partnerships [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	4,728	54,652
Total [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	949,007	836,770
Fair Value, Inputs, Level 1 [Member] | Debt Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	0	0
Fair Value, Inputs, Level 1 [Member] | Commodity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets		0
Fair Value, Inputs, Level 1 [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	549	246
Fair Value, Inputs, Level 1 [Member] | Investments In The Fair Value Hierarchy [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	549	246
Fair Value, Inputs, Level 2 [Member] | Debt Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	435,692	168,953
Fair Value, Inputs, Level 2 [Member] | Commodity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets		14,697
Fair Value, Inputs, Level 2 [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	120,253	135,656
Fair Value, Inputs, Level 2 [Member] | Investments In The Fair Value Hierarchy [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	555,945	319,306
Fair Value, Inputs, Level 3 | Debt Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	0	0
Fair Value, Inputs, Level 3 | Commodity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets		0
Fair Value, Inputs, Level 3 | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	0	0
Fair Value, Inputs, Level 3 | Investments In The Fair Value Hierarchy [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	$ 0	$ 0