Supplemental Cash Flow Information (Tables)

12 Months Ended

Dec. 31, 2017

Supplemental Cash Flow Elements [Abstract]

Schedule of Supplemental Disclosures of Cash Flow Information

	Year Ended December 31
	2017			2016		2015
	(In thousands)
Cash paid for interest and financing charges, net of capitalized interest	$	60,403		$	60,580	$	49,593
Net cash paid (received) for taxes	(3,063		)	50,630		(29,157		)
Non-cash additions to property, plant and equipment, including capital leases	8,879			4,748		10,129