EMPLOYEE BENEFIT PLANS

6 Months Ended

Jun. 30, 2017

Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]

EMPLOYEE BENEFIT PLANS

EMPLOYEE BENEFIT PLANS

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	2017			2016			2017			2016
Components of net periodic benefit cost:
Service cost	$	10,144		$	7,339		$	20,287		$	14,679
Interest cost	1,084			775			2,168			1,551
Expected return on plan assets	(1,442		)	(1,107		)	(2,884		)	(2,213		)
Amortization of prior service cost	13			13			26			26
Amortization of actuarial loss (gain)	113			194			226			388
Net periodic benefit cost	$	9,912		$	7,214		$	19,823		$	14,431

	Three Months Ended   June 30,				Six Months Ended   June 30,
Post-Retirement Medical Plan	2017		2016		2017		2016
Components of net periodic benefit cost:
Service cost	$	316	$	219	$	632	$	439
Interest cost	172		133		344		267
Amortization of prior service cost	161		109		322		218
Amortization of actuarial loss (gain)	—		—		—		—
Net periodic benefit cost	$	649	$	461	$	1,298	$	924