PENSION AND OTHER POSTRETIREMENT BENEFITS

We have a noncontributory defined benefit pension plan covering substantially all employees first hired prior to July 1, 2015 after the completion of one year of service and 1,000 hours of service. The plan provides retirement benefits based on an employee’s average earnings and years of service. These employees become 100% vested after three years of service, regardless of age. A supplemental benefit plan provides nonqualified benefits for compensation in excess of the IRS compensation limits applicable to the plan.

Our plan funding policy is to make contributions, provided that the total annual contributions will not be less than ERISA and the Pension Protection Act of 2006 minimums or greater than the maximum tax-deductible amount, to review the contribution and funding strategy on a regular basis, and to allow discretionary contributions to be made by us from time to time. The assets of the defined benefit pension plan are invested primarily in fixed income investments and equity securities. We pay nonqualified pension benefits when they are due according to the terms of the supplemental benefit plan.

We provide certain postretirement health care and life insurance benefits to retired employees. Substantially all of our employees hired or rehired prior to 2014 may become eligible for postretirement medical benefits if they reach the age and service requirements of the retiree medical plan and retire on a service pension (except a deferred pension) under the defined benefit pension plan. Medical benefits are self-insured and claims are administered through an insurance company. The cost of coverage is determined based on the annual projected plan costs. The participant's premium or cost is determined based on Company guidelines. Postretirement life insurance benefits are insured through an insurance company. We fund postretirement benefits as incurred, and accordingly, there were no assets held in the postretirement benefits plan at September 30, 2017 and December 31, 2016.

The net periodic benefit cost for the three and nine months ended September 30, 2017 and 2016 includes the following components:



	Pension Benefits						Postretirement Benefits
	Three Months Ended September 30,						Three Months Ended September 30,
	Three Months Ended September 30,						Three Months Ended September 30,
Components of Net Periodic Benefit Cost	2017			2016			2017			2016
Service cost	$	6,604		$	6,342		$	582		$	572
Interest cost	6,954			7,066			711			757
Expected return on plan assets	(7,658		)	(6,754		)	—			—
Amortization of:
Net actuarial loss	5,376			4,791			197			177
Prior service cost (gain)	105			106			(545		)	(545		)
Net periodic benefit cost	$	11,381		$	11,551		$	945		$	961

	Pension Benefits						Postretirement Benefits
	Nine Months Ended September 30,						Nine Months Ended September 30,
	Nine Months Ended September 30,						Nine Months Ended September 30,
Components of Net Periodic Benefit Cost	2017			2016			2017			2016
Service cost	$	19,812		$	19,026		$	1,745		$	1,716
Interest cost	20,863			21,197			2,133			2,272
Expected return on plan assets	(22,973		)	(20,262		)	—			—
Amortization of:
Net actuarial loss	16,127			14,373			591			531
Prior service cost (gain)	315			318			(1,635		)	(1,635		)
Net periodic benefit cost	$	34,144		$	34,652		$	2,834		$	2,884

We made qualified and nonqualified pension contributions totaling $24,001 and $44,002 during the three-month periods ended September 30, 2017 and 2016, respectively. Contributions made during the nine-month periods ending September 30, 2017 and 2016 totaled $61,587 and $81,633, respectively. Additional contributions totaling $2 are expected to be paid during the remainder of 2017.