EMPLOYEE BENEFIT PLANS - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	1 Months Ended	11 Months Ended	12 Months Ended
	Jan. 31, 2015	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2014
Defined Benefit Pension Plan
EMPLOYEE BENEFIT PLANS
Average remaining service period used			9 years 3 months 22 days
Successor | Defined Benefit Pension Plan
EMPLOYEE BENEFIT PLANS
Service cost—benefits earned during the period		$ 11,220	$ 12,791
Interest cost on projected benefit obligation		9,072	9,751
Expected return on plan assets		(13,214)	(13,780)
Amortization of prior service cost/(credit)		0	0
Amortization of actuarial loss/(gain)		0	0
Preliminary net periodic benefit cost		7,078	8,762
Settlement/curtailment expense		0	(964)
Total net periodic benefit cost		7,078	7,798
Successor | Unfunded Excess Benefits Plan
EMPLOYEE BENEFIT PLANS
Service cost—benefits earned during the period		1,229	1,413
Interest cost on projected benefit obligation		1,499	1,353
Expected return on plan assets		0	0
Amortization of prior service cost/(credit)		0	0
Amortization of actuarial loss/(gain)		0	178
Preliminary net periodic benefit cost		2,728	2,944
Settlement/curtailment expense		0	2,135
Total net periodic benefit cost		$ 2,728	$ 5,079
Predecessor | Defined Benefit Pension Plan
EMPLOYEE BENEFIT PLANS
Service cost—benefits earned during the period	$ 974			$ 9,411
Interest cost on projected benefit obligation	1,002			10,493
Expected return on plan assets	(1,293)			(12,166)
Amortization of prior service cost/(credit)	(33)			(392)
Amortization of actuarial loss/(gain)	668			6,821
Preliminary net periodic benefit cost	1,318			14,167
Settlement/curtailment expense	0			0
Total net periodic benefit cost	1,318			14,167
Predecessor | Unfunded Excess Benefits Plan
EMPLOYEE BENEFIT PLANS
Service cost—benefits earned during the period	95			954
Interest cost on projected benefit obligation	140			1,696
Expected return on plan assets	0			0
Amortization of prior service cost/(credit)	1			12
Amortization of actuarial loss/(gain)	138			1,516
Preliminary net periodic benefit cost	374			4,178
Settlement/curtailment expense	0			0
Total net periodic benefit cost	$ 374			$ 4,178
Minimum | Unfunded Excess Benefits Plan
EMPLOYEE BENEFIT PLANS
Average remaining service period used			8 years 6 months 29 days
Maximum | Unfunded Excess Benefits Plan
EMPLOYEE BENEFIT PLANS
Average remaining service period used			8 years 7 months 17 days