BENEFIT PLANS (Employer Contributions for Plan) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 6,099	$ 4,871	$ 5,280
2019 (estimated)	5,561
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	109,631	20,023	$ 9,576
Employer contributions	54,679	$ 51,234
2019 (estimated)	$ 9,067