Net Income (Loss) Per Share (Tables)

12 Months Ended

Dec. 31, 2013

Earnings Per Share [Abstract]

Basic and Diluted Net Income (Loss) Per Share

The calculations of basic and diluted net income (loss) per share are as follows:

	December 31,
	2013		2012		2011
Net income (loss) - basic	$	424,362	$	750,269	$	(221,760	)
Effect of dilutive securities:
Convertible senior notes - interest expense related to contractual coupon interest rate and amortization of discount and note issuance costs, net of tax	—		29,126		—
Net income (loss) - diluted	$	424,362	$	779,395	$	(221,760	)
(Shares in thousands)
Weighted average shares - basic	97,917		94,685		90,610
Effect of dilutive securities:
Stock options	10,233		14,231		—
Restricted stock	433		715		—
Convertible senior notes	—		4,761		—
Warrants	2,707		990		—
Dilutive potential shares	13,373		20,697		—
Weighted average shares - diluted	111,290		115,382		90,610
Net income (loss) per share - basic	$	4.33	$	7.92	$	(2.45	)
Net income (loss) per share - diluted	$	3.81	$	6.75	$	(2.45	)

Antidilutive Securities

Shares which have been excluded from the December 31, 2013, 2012, and 2011 diluted per share amounts because their effect would have been antidilutive, include the following:

	December 31,
(Shares in thousands)	2013	2012	2011
Stock options	304	325	20,942
Restricted stock	—	—	846
Convertible senior notes	4,761	—	939
Warrants	—	—	939