ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Tax benefit	$ (7,182)	$ (10,341)	$ (12,946)	$ (20,621)
Net of tax			28,352
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Prior service credits	(371)	(280)	(742)	(560)
Actuarial losses	155	61	310	122
Total before tax	(216)	(219)	(432)	(438)
Tax benefit	78	83	157	166
Net of tax	$ (138)	$ (136)	$ (275)	$ (272)