DEFINED BENEFIT PLANS - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Retirement Benefits [Abstract]
Net periodic benefit costs	$ 0.6	$ 1.1
Service cost component	0.7	1.4
Expected future employer contributions, next fiscal year			$ 1.8
Employer contributions		1.0
Expected additional employer contributions	1.0	1.0
Expected employer contributions, this fiscal year	2.0	2.0
Estimated fair value of plan assets	$ 29.2	$ 29.2	$ 26.9