EMPLOYEE BENEFIT PLANS (Included in AOCI) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Nonunion Defined Benefit Pension Plan
Pre-tax amounts included in accumulated other comprehensive loss that have not yet been recognized in net periodic benefit cost
Unrecognized net actuarial loss	$ 23,294	$ 28,457
Total	23,294	28,457
Pre-tax amounts, which are reported within accumulated other comprehensive loss, expected to be recognized as components of net periodic benefit cost in next fiscal year
Unrecognized net actuarial loss	2,960
Total	2,960
Supplemental Benefit Plan
Pre-tax amounts included in accumulated other comprehensive loss that have not yet been recognized in net periodic benefit cost
Unrecognized net actuarial loss	635	1,001
Total	635	1,001
Pre-tax amounts, which are reported within accumulated other comprehensive loss, expected to be recognized as components of net periodic benefit cost in next fiscal year
Unrecognized net actuarial loss	109
Total	109
Postretirement Health Benefit Plan
Pre-tax amounts included in accumulated other comprehensive loss that have not yet been recognized in net periodic benefit cost
Unrecognized net actuarial loss	5,708	6,280
Unrecognized prior service credit	(317)	(507)
Total	5,391	$ 5,773
Pre-tax amounts, which are reported within accumulated other comprehensive loss, expected to be recognized as components of net periodic benefit cost in next fiscal year
Unrecognized net actuarial loss	620
Unrecognized prior service credit	(190)
Total	$ 430