Net Income (Loss) Per Share (Tables)

12 Months Ended

Dec. 31, 2015

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	Year ended December 31,
In thousands except per share amounts	2015			2014			2013
Net income (loss) available to common stockholders	$	(367,183	)	$	(1,186,874	)	$	(650,563	)
Weighted average shares:
Basic	129,639			102,441			97,864
Effect of stock-based compensation plans	—			—			—
Diluted	129,639			102,441			97,864
Income (loss) per share:
Basic	$	(2.83	)	$	(11.59	)	$	(6.65	)
Diluted	$	(2.83	)	$	(11.59	)	$	(6.65	)