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		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Retirement Benefits [Abstract]
Service cost	$ 2,079	$ 1,649	$ 5,855	$ 4,944
Interest cost	624	694	1,831	2,083
Expected return on plan assets	(2,443)	(2,429)	(7,382)	(7,288)
Amortization of prior service cost	(106)	(104)	(308)	(310)
Defined Benefit Plan, Amortization of Gain (Loss)	625	451	1,709	1,352
Net periodic benefit cost (income)	$ 779	$ 261	$ 1,705	$ 781