Net Income (Loss) Per Share (Tables)

9 Months Ended

Sep. 30, 2016

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted

	Three months ended September 30,					Nine months ended September 30,
In thousands except per share amounts	2016		2015			2016		2015
Net income (loss) available to common stockholders	$	69,557	$	(14,219	)	$	63,660	$	(64,185	)
Weighted average shares:
Basic	161,039		135,247			155,108		124,478
Effect of stock-based compensation plans	4,789		—			3,284		—
Diluted	165,828		135,247			158,392		124,478
Income (loss) per share:
Basic	$	0.43	$	(0.11	)	$	0.41	$	(0.52	)
Diluted	$	0.42	$	(0.11	)	$	0.40	$	(0.52	)