COMMITMENTS AND CONTINGENCIES - Insurance Programs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Health insurance	$ 14.1	$ 10.6
Workers’ compensation	29.3	26.8
Professional liability	4.3	4.7
Estimated Insurance Total	47.7	42.1
Less: long-term portion	(1.2)	(0.8)
Estimated Insurance Excluding Long Term Portion	$ 46.5	$ 41.3