Pension Plans and Postretirement Benefits ASU 2017-07 Compensation Retirement Benefits (Topic 715) (Policies)

12 Months Ended

Dec. 31, 2017

Postemployment Benefits [Abstract]

Postemployment Benefit Plans, Policy [Policy Text Block]

The changes in the classification of the historical components of net periodic benefit costs are summarized in the following table:

Pension & other postretirement benefit costs (benefits)
(in thousands)	December 31, 2017			December 31, 2016			December 31, 2015			Current classification	Future classification
Service cost	$	804		$	1,703		$	13,701		Cost of operations	Cost of operations
Interest cost	41,432			41,772			50,644			Cost of operations	Other income (expense)
Expected return on plan assets	(59,409		)	(61,939		)	(68,709		)	Cost of operations	Other income (expense)
Amortization of prior service cost	(2,906		)	250			307			Cost of operations	Other income (expense)
Recognized net actuarial losses and mark to market adjustments	(8,696		)	24,110			40,210			Cost of operations or SG&A expense	Other income (expense)
Net periodic benefit cost (benefit)	$	(28,775	)	$	5,896		$	36,153