Nature of Operations and Basis of Consolidation Retirement Benefits (Tables)

3 Months Ended

Mar. 31, 2018

Income Statement [Abstract]

New Accounting Pronouncements and Changes in Accounting Principles [Text Block]

The following table summarizes the adjustments made to conform prior period classifications to the new guidance (in thousands):

	Three Months Ended March 31, 2017
	As Reported		Effect of Accounting Change			As Adjusted
Operating, general and administrative	$	80,962	$	(2,628	)	$	78,334
Other Income (Expense), net	1,500		(2,628		)	(1,128		)

	As Reported		Effect of Accounting Change			As Adjusted
	Year Ended December 31, 2017
Operating, general and administrative	$	305,137	$	(10,334	)	$	294,803
Other Income (Expense), net	6,919		(10,334		)	(3,415		)
	Year Ended December 31, 2016
Operating, general and administrative	$	302,893	$	(9,030	)	$	293,863
Other Income (Expense), net	5,548		(9,030		)	(3,482		)
	Year Ended December 31, 2015
Operating, general and administrative	$	297,475	$	(6,757	)	$	290,718
Other Income (Expense), net	7,583		(6,757		)	826