Note 11. Employee Benefits

The components of net periodic benefit cost (credit) for our defined benefit plans and postretirement benefit plans for the three months and nine months ended September 30, 2013 and 2012 were as follows (in thousands):

	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2013			2012			2013			2012
Pension benefits
Service cost	$	45		$	32		$	135		$	97
Interest cost		59			47			176			140
Amortization of prior service cost		7			28			21			83
Actuarial net loss		172			65			517			196
Net periodic benefit cost	$	283		$	172		$	849		$	516

Postretirement benefits
Service cost	$	—		$	1		$	1		$	3
Interest cost		9			22			28			65
Amortization of prior service benefit		(1,085	)		(1,225	)		(3,259	)		(3,672	)
Actuarial net loss		609			708			1,825			2,125
Net periodic benefit credit	$	(467	)	$	(494	)	$	(1,405	)	$	(1,479	)

For the nine months ended September 30, 2013, we made employee benefit contributions of $0.7 million related to our postretirement plans. Based on current estimates, we believe we will be required to make approximately $1 million in contributions for 2013.

We maintain a Supplemental Executive Retirement Plan for key employees. Under the plan, these employees may elect to defer a portion of their compensation and, in addition, we may at our discretion make contributions to the plan on behalf of the employees. In March 2013, contributions of $0.5 million were made to the plan related to calendar year 2012.

We also have an Employee Stock Ownership Plan and Trust for employees who are not covered by a collective bargaining agreement. In connection therewith, we maintain an employee benefits trust to which we contribute shares of treasury stock. We are authorized to instruct the trustees to distribute such shares toward the satisfaction of our future obligations under the plan. The shares held in trust are not considered outstanding for purposes of calculating earnings per share until they are committed to be released. The trustees will vote the shares in accordance with their fiduciary duties. During 2013, we contributed to the trust an additional 182,000 shares from our treasury and released 182,500 shares from the trust leaving 430 shares remaining in the trust as of September 30, 2013.