BENEFIT PLANS (Fair Values of Pension Plan Assets) (Details) - Pension Benefits [Member] - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	$ 168,953	$ 178,512
Commodity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	14,697	17,041
Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	135,902	144,099
Investments In The Fair Value Hierarchy [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	319,552	339,652
Interest In Common/Collective Trusts [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	462,566	416,397
Private Partnerships [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	54,652	84,852
Total [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	836,770	840,901
Level 1 [Member] | Debt Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	0	0
Level 1 [Member] | Commodity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	0	0
Level 1 [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	246	1,089
Level 1 [Member] | Investments In The Fair Value Hierarchy [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	246	1,089
Level 2 [Member] | Debt Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	168,953	178,512
Level 2 [Member] | Commodity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	14,697	17,041
Level 2 [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	135,656	143,010
Level 2 [Member] | Investments In The Fair Value Hierarchy [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	319,306	338,563
Level 3 [Member] | Debt Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	0	0
Level 3 [Member] | Commodity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	0	0
Level 3 [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	0	0
Level 3 [Member] | Investments In The Fair Value Hierarchy [Member]
Defined Benefit Plan Disclosure [Line Items]
Total pension plan assets	$ 0	$ 0