Pension Benefits (Tables)

6 Months Ended

Jun. 30, 2018

Defined Benefit Plan [Abstract]

Components of the net periodic benefit cost for the Pension Plans [Table Text Block]

The following table presents the components of the net periodic benefit cost for the Pension Plans:

	For the Three Months Ended   June 30,						For the Six Months Ended   June 30,
	2018			2017			2018			2017
	(in thousands)
Service cost	$	1,705		$	1,269		$	3,365		$	3,319
Interest cost	637			617			1,310			1,344
Expected return on plan assets that reduces periodic pension benefit cost	(370		)	(563		)	(931		)	(1,122		)
Amortization of prior service cost	5			5			9			9
Amortization of net actuarial loss	340			253			664			649
Net periodic benefit cost	$	2,317		$	1,581		$	4,417		$	4,199