MULTI-EMPLOYER WITHDRAWAL LIABILITY (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	May. 29, 2015
Multiemployer withdrawal liability
Benefit payment period	18 years
Estimated future benefit payments
Current portion of withdrawal liability	$ (4.1)
Horizon
Multiemployer withdrawal liability
Quarterly payments to ILA-PRSSA over an estimated period	$ 1.0
Benefit payment period	18 years
Estimated future benefit payments
2016	$ 4.1
2017	4.1
2018	4.1
2019	4.1
2020	4.1
Thereafter	52.3
Total	72.8	$ 73.9
Less: amount representing interest	(12.5)
Present value of remaining withdrawal liability	60.3
Current portion of withdrawal liability	(4.1)
Long-term portion of withdrawal liability	$ 56.2