DEFINED BENEFIT PLANS - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Retirement Benefits [Abstract]
Net periodic benefit costs	$ 500,000	$ 600,000
Service cost component	700,000	$ 700,000
Expected future employer contributions, next fiscal year			$ 1,900,000
Employer contributions	0
Expected additional employer contributions	1,900,000
Estimated fair value of plan assets	$ 30,100,000		$ 31,100,000