Defined Benefit Pension Plans (Tables)

6 Months Ended

Jun. 30, 2017

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

Schedule of Amounts Recognized in the Consolidated Balance Sheets [Table Text Block]

Amounts recognized on the Consolidated Balance Sheets consist of:

	June 30, 2017		December 31, 2016
	(in thousands)
Assets
Plan assets in other long-term assets	$	702	$	654
Liabilities
Current portion of pension benefit obligation in wages and benefits payable	3,340		3,202
Long-term portion of pension benefit obligation	93,263		84,498
Pension benefit obligation, net	$	95,901	$	87,046

Schedule of Net Periodic Pension Benefit Costs [Table Text Block]

Net periodic pension benefit costs for our plans include the following components:

	Three Months Ended June 30,						Six Months Ended June 30,
	2017			2016			2017			2016
	(in thousands)
Service cost	$	924		$	941		$	1,852		$	1,927
Interest cost	535			650			1,060			1,283
Expected return on plan assets	(147		)	(133		)	(293		)	(259		)
Settlements and other	—			(4		)	—			(7		)
Amortization of actuarial net loss	403			334			794			661
Amortization of unrecognized prior service costs	15			16			30			31
Net periodic benefit cost	$	1,730		$	1,804		$	3,443		$	3,636