EMPLOYEE BENEFITS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance at beginning of year	$ 180,007
Balance at end of year	180,749	$ 180,007
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Pension and postretirement liabilities	(58,840)	(57,322)
Pension Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	234,350	235,433
Service cost	2,178	1,953	$ 1,421
Interest cost	6,624	6,676	8,426
Plan participants' contributions	1,516	1,516
Actuarial loss (gain)	7,117	(610)
Foreign currency impact	(4,686)	(2,197)
Benefits and administrative expenses paid	(8,579)	(8,619)
Settlements	(2,694)	(37)
Acquisitions	0	235
Benefit obligation at end of year	235,826	234,350	235,433
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance at beginning of year	180,007	185,981
Actual return on plan assets	10,347	(597)
Employer contributions	4,214	3,362
Foreign currency impact	(4,063)	(1,599)
Settlements	(2,694)	(37)
Balance at end of year	180,748	180,007	185,981
Funded status of plans	(55,078)	(54,343)
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Non-current assets	2,387	1,638
Current liabilities	(260)	(264)
Pension and postretirement liabilities	(57,205)	(55,717)
Net amount recognized	(55,078)	(54,343)
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax [Abstract]
Net actuarial (loss) gain	(80,837)	(80,641)
Transition asset	0	249
Prior service credit	1,474	1,804
Accumulated other comprehensive (loss) income	(79,363)	(78,588)
Accumulated contributions in excess of net periodic benefit cost	24,285	24,245
Net amount recognized	(55,078)	(54,343)
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	1,683	1,806
Service cost	11	12	11
Interest cost	76	74	87
Plan participants' contributions	292	338
Actuarial loss (gain)	67	(100)
Foreign currency impact	0	0
Benefits and administrative expenses paid	(400)	(447)
Settlements	0	0
Acquisitions	0	0
Benefit obligation at end of year	1,729	1,683	1,806
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Balance at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	108	109
Foreign currency impact	0	0
Settlements	0	0
Balance at end of year	0	0	$ 0
Funded status of plans	(1,729)	(1,683)
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Non-current assets	0	0
Current liabilities	(126)	(112)
Pension and postretirement liabilities	(1,603)	(1,571)
Net amount recognized	(1,729)	(1,683)
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax [Abstract]
Net actuarial (loss) gain	581	706
Transition asset	0	0
Prior service credit	0	0
Accumulated other comprehensive (loss) income	581	706
Accumulated contributions in excess of net periodic benefit cost	(2,310)	(2,389)
Net amount recognized	$ (1,729)	$ (1,683)