EMPLOYEE BENEFIT PLANS (Details 6) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)	100.00%
Total (as a percent)		100.00%	100.00%
Total		$ 194,342	$ 190,640	$ 192,163
Percentage of investments for long-term growth, investment strategy mix		70.00%
Percentage of investments for near-term benefit payments, investment strategy mix		30.00%
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total		$ 60,568	56,061
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total		115,004	115,147
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total		$ 18,770	$ 19,432
Cash [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)	0.00%
Cash [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)	5.00%
Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)		21.70%	21.20%
Total		$ 42,120	$ 40,510
Common Stock [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total		$ 42,120	$ 40,510
Common Stock [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)	0.00%
Common Stock [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)	40.00%
Domestic Equity Securities Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)		20.70%	20.50%
Total		$ 40,178	$ 39,070
Domestic Equity Securities Other [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total		11,614	12,008
Domestic Equity Securities Other [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total		$ 28,564	$ 27,062
Domestic Equity Securities Other [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)	0.00%
Domestic Equity Securities Other [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)	40.00%
International equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)		21.00%	22.20%
Total		$ 40,767	$ 42,373
International equity [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total
International equity [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total		$ 40,767	$ 42,373
International equity [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)	0.00%
International equity [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)	30.00%
Debt securities - core fixed income [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)		23.50%	24.00%
Total		$ 45,673	$ 45,712
Debt securities - core fixed income [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total
Debt securities - core fixed income [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total		$ 45,673	$ 45,712
Debt securities - core fixed income [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)	15.00%
Debt securities - core fixed income [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)	50.00%
Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)		6.40%	6.60%
Total		$ 12,527	$ 12,565
Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total		$ 12,527	$ 12,565
Real Estate [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)	0.00%
Real Estate [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)	20.00%
Real Return Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)	0.00%
Total (as a percent)			0.00%
Alternative/Opportunistic/Special [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)		3.20%	3.60%
Total		$ 6,243	$ 6,867
Alternative/Opportunistic/Special [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total		$ 6,243	$ 6,867
Alternative/Opportunistic/Special [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)	0.00%
Alternative/Opportunistic/Special [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)	20.00%
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Total (as a percent)		3.50%	1.90%
Total		$ 6,834	$ 3,543
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total		$ 6,834	$ 3,543