EMPLOYEE BENEFIT PLANS - Employee benefit plan amounts recognized in the Consolidated Balance Sheets and Consolidated Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Retirement Benefits [Abstract]
Service cost	$ 1,545	$ 1,735	$ 3,295	$ 3,030
Interest cost	689	601	1,389	1,191
Expected return on plan assets	(2,409)	(2,450)	(4,859)	(4,910)
Amortization of prior service cost	(106)	(103)	(206)	(206)
Defined Benefit Plan, Amortization of Gain (Loss)	426	555	901	1,077
Net periodic benefit cost (income)	$ 145	$ 338	$ 520	$ 182