Supplemental Cash Flow Information (Tables)

12 Months Ended

Dec. 31, 2018

Supplemental Cash Flow Information [Abstract]

Schedule of Cash Flow, Supplemental Disclosure

Supplemental Cash Flow Information

	Year Ended December 31,
In thousands	2018			2017			2016
Supplemental cash flow information
Cash paid for interest, expensed	$	50,076		$	98,261		$	130,843
Cash paid for interest, capitalized	37,079			30,762			25,982
Cash paid for interest, treated as a reduction of debt	79,606			50,349			25,835
Cash paid for income taxes	492			450			375
Cash received from income tax refunds	(8,280		)	(13,323		)	(2,455		)
Noncash investing and financing activities
Increase in asset retirement obligations	4,499			9,565			11,621
Increase (decrease) in liabilities for capital expenditures	14,600			3,930			(13,593		)
Conversion of convertible senior notes into common stock	162,004			—			—
Retirement of treasury stock	—			46,562			—