EMPLOYEE BENEFIT PLANS - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jan. 31, 2015
EMPLOYEE BENEFIT PLANS
Percentage change in healthcare cost trend assumptions which has no material effect on liability related to prescription drug benefit provided to employees	1.00%
Period for which the average and annualized return on Barclay's short treasury index is considered for assessment of reasonableness of long term rate of return assumption	25 years
Defined Benefit Pension Plan
EMPLOYEE BENEFIT PLANS
Adjusted funding target percentage subject to benefit restrictions, maximum	80.00%
Adjusted funding target percentage to be maintained (at least)	80.00%
Contribution made by the company to its defined benefit pension plan year 2015	$ 1,900,000
Contribution made by the company to its defined benefit pension plan year 2016	19,000,000
Defined Benefit Pension Plan | Minimum
EMPLOYEE BENEFIT PLANS
Estimated contribution by employer	1,000,000
Defined Benefit Pension Plan | Maximum
EMPLOYEE BENEFIT PLANS
Estimated contribution by employer	10,000,000
Unfunded Excess Benefits Plan
EMPLOYEE BENEFIT PLANS
Amortized loss from other comprehensive income into net periodic benefit	$ 200,000
Other Postretirement Benefits | Maximum
EMPLOYEE BENEFIT PLANS
Age of eligibility for limited healthcare benefits	65 years
Retiree medical plan | Minimum
EMPLOYEE BENEFIT PLANS
Age of eligibility for prescription drug benefit	65 years
Life insurance benefits	$ 10,000
Retiree medical plan | Maximum
EMPLOYEE BENEFIT PLANS
Life insurance benefits	75,000
Group life insurance plan
EMPLOYEE BENEFIT PLANS
Face amount of life insurance benefits funded	$ 50,000
Successor | Defined Benefit Pension Plan
EMPLOYEE BENEFIT PLANS
Discount rate (as a percent)	4.04%	4.29%
Discount rate (as a percent)	4.29%
Accumulated benefit obligation, end of year	$ 247,595,000	$ 250,133,000
Successor | Unfunded Excess Benefits Plan
EMPLOYEE BENEFIT PLANS
Discount rate (as a percent)	3.60%	3.63%
Discount rate (as a percent)	3.63%
Accumulated benefit obligation, end of year	$ 45,594,000	$ 54,196,000
Successor | Other Postretirement Benefits
EMPLOYEE BENEFIT PLANS
Accumulated benefit obligation, end of year	$ 100,000	$ 100,000
Successor | Retiree medical plan
EMPLOYEE BENEFIT PLANS
Discount rate (as a percent)	1.70%
Discount rate (as a percent)	1.54%
Liability related to prescription drug benefit provided to employees	$ 100,000
Successor | Group life insurance plan
EMPLOYEE BENEFIT PLANS
Discount rate (as a percent)	4.35%
Discount rate (as a percent)	4.60%
Predecessor | Defined Benefit Pension Plan
EMPLOYEE BENEFIT PLANS
Discount rate (as a percent)			3.55%
Discount rate (as a percent)		3.95%	4.86%
Accumulated benefit obligation, end of year				$ 262,290,000
Predecessor | Unfunded Excess Benefits Plan
EMPLOYEE BENEFIT PLANS
Discount rate (as a percent)			3.26%
Discount rate (as a percent)		3.65%	4.30%
Accumulated benefit obligation, end of year				$ 49,251,000
Predecessor | Retiree medical plan
EMPLOYEE BENEFIT PLANS
Liability related to prescription drug benefit provided to employees		$ 100,000