Postretirement Medical Plan

6 Months Ended

Jun. 30, 2015

Postretirement Medical Plan

Pension and Other Postretirement Benefits Disclosure [Text Block]

14. Postretirement Medical Plan

We maintain an unfunded postretirement medical plan to provide certain postretirement medical benefits to eligible employees. Net periodic postretirement benefit costs included the following components (in thousands):

		Three Months Ended				Six Months Ended
		June 30,				June 30,
		2015		2014		2015		2014
Service cost		$	1,229	$	1,038	$	2,458	$	2,075
Interest cost			482		464		964		929
Amortization of prior service cost			313		247		626		494
	Net periodic benefit cost	$	2,024	$	1,749	$	4,048	$	3,498