PENSION AND POST-RETIREMENT PLANS - DEFINED CONTRIBUTION PLANS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
401(K) plan
Defined Contribution Plans
Employer matching contribution (as a percent)	3.00%
Employer matching contribution expenses	$ 2.4	$ 2.4	$ 2.1
Profit sharing plan
Defined Contribution Plans
Profit sharing expense recorded	$ 1.4	$ 2.3	$ 0.0