EMPLOYEE BENEFIT PLANS (Tables)

6 Months Ended

Jun. 30, 2018

Defined Benefit Plan [Abstract]

Schedule of net periodic benefit cost

The components of net periodic benefit cost related to the Company’s defined benefit plans consisted of the following:

	Three Months Ended   June 30,						Six Months Ended   June 30,
Pension Benefits	2018			2017			2018			2017
Components of net periodic benefit cost:
Service cost	$	11,836		$	10,144		$	23,672		$	20,287
Interest cost	1,449			1,084			2,896			2,168
Expected return on plan assets	(2,136		)	(1,442		)	(4,270		)	(2,884		)
Amortization of prior service cost	22			13			43			26
Amortization of actuarial loss	72			113			143			226
Net periodic benefit cost	$	11,243		$	9,912		$	22,484		$	19,823

	Three Months Ended   June 30,				Six Months Ended   June 30,
Post-Retirement Medical Plan	2018		2017		2018		2017
Components of net periodic benefit cost:
Service cost	$	287	$	316	$	574	$	632
Interest cost	155		172		310		344
Amortization of prior service cost	161		161		323		322
Net periodic benefit cost	$	603	$	649	$	1,207	$	1,298