DEFINED CONTRIBUTION PLANS (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]      
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Minimum Pension Liability, before Tax $ 18,817 $ 19,271  
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax (18,817) (19,271)  
Defined Benefit Plan, Contributions by Employer $ 600 1,800  
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay 6.00%    
Defined Contribution Plan, Cost Recognized $ 3,700 $ 3,600 $ 2,200
Employees not subject to collective bargaining agreement [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Employer matching contribution (in hundredths) 50.00%