EMPLOYEE BENEFIT PLANS - Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	$ 14,223	$ 13,906	$ 14,258
Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	14,223	13,906
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	1,218	1,606
Cash and cash equivalents | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	1,218	1,606
Mutual funds - taxable fixed income
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	1,467	1,732
Mutual funds - taxable fixed income | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	1,467	1,732
Mutual funds - domestic equity
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	8,150	8,372
Mutual funds - domestic equity | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	8,150	8,372
Mutual funds - international equity
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	631	2,196
Mutual funds - international equity | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	631	$ 2,196
Inflation Hedges/Real Assets
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	715
Inflation Hedges/Real Assets | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	715
Hedged Strategies
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	2,042
Hedged Strategies | Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets at fair value	$ 2,042