EMPLOYEE BENEFIT PLANS 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
	Mar. 31, 2018	Mar. 31, 2017
Retirement Benefits [Abstract]
Service cost	$ 1,295	$ 1,238
Interest cost	590	589
Expected return on plan assets	(2,460)	(2,481)
Amortization of prior service cost	(103)	(103)
Defined Benefit Plan, Amortization of Gain (Loss)	522	438
Net periodic benefit cost (income)	$ (156)	$ (319)