DEFINED BENEFIT PLANS - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Retirement Benefits [Abstract]
Net periodic benefit costs	$ 0.5	$ 1.7
Service cost component	0.7	2.1
Expected future employer contributions, next fiscal year			$ 1.8
Employer contributions		1.1
Expected additional employer contributions	0.9	0.9
Expected employer contributions, this fiscal year	2.0	2.0
Estimated fair value of plan assets	$ 30.4	$ 30.4	$ 26.9