Employee Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2019

Retirement Benefits [Abstract]

Schedule of Defined Benefit Plans Disclosures [Table Text Block]

Net periodic benefit cost (income) for our pension and other postretirement plans consists of the following (in thousands):

	Pension Benefits						Other Postretirement Benefits
	Three Months Ended June 30,						Three Months Ended June 30,
	2019			2018			2019			2018
Components of Net Periodic Benefit Cost (Income)
Service cost	$	2,322		$	2,684		$	77		$	87
Interest cost	6,615			6,102			150			142
Expected return on plan assets	(6,360		)	(7,044		)	(217		)	(238		)
Amortization of prior service cost (credit)	1,620			1			(470		)	(470		)
Recognized actuarial loss (gain)	—			1,108			(24		)	(20		)
Net Periodic Benefit Cost (Income)	$	4,197		$	2,851		$	(484	)	$	(499	)

	Pension Benefits						Other Postretirement Benefits
	Six Months Ended June 30,						Six Months Ended June 30,
	2019			2018			2019			2018
Components of Net Periodic Benefit Cost (Income)
Service cost	$	4,819		$	5,888		$	166		$	199
Interest cost	13,244			12,210			305			289
Expected return on plan assets	(12,722		)	(14,104		)	(435		)	(477		)
Amortization of prior service cost	3,272			2			(941		)	(941		)
Recognized actuarial loss (gain)	—			2,180			(48		)	(40		)
Net Periodic Benefit Cost (Income)	$	8,613		$	6,176		$	(953	)	$	(970	)