Net Loss Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Earnings Per Share [Abstract]
Net income (loss)	$ (98,902)		$ (100,724)		$ (342,471)		$ (184,660)
Denominator:
Average number of common shares outstanding, Basic	66,952,000	[1]	62,573,000	[1]	64,986,000	[1]	62,555,000	[1]
Average number of common shares outstanding, Diluted	66,952,000	[1]	62,573,000	[1]	64,986,000	[1]	62,555,000	[1]
Net loss per share, Basic (in dollars per share)	$ (1.48)		$ (1.61)		$ (5.27)		$ (2.95)
Net loss per share, Diluted (in dollars per share)	$ (1.48)		$ (1.61)		$ (5.27)		$ (2.95)
Anti-dilutive securities excluded from earnings per share calculation	1,727		675		1,437		525
Share-based awards exercised or released
Stock options exercised	0		0		18,300		24,831
Restricted stock units vested	3,337		4,558		81,889		30,234
Total	3,337		4,558		100,189		55,065

[1] In periods of net loss, the number of shares used to calculate diluted earnings per share is the same as basic earnings per share; therefore, the effect of dilutive securities is zero for such periods. The weighted average number of stock options and restricted stock units outstanding for the three months ended September 30, 2014 and 2013 totaling 1,727 and 675, respectively, were excluded from the calculation above because their effect would have been anti-dilutive. Additionally, the weighted average number of stock options and restricted stock units outstanding for the nine months ended September 30, 2014 and 2013 totaling 1,437 and 525, respectively, were excluded from the calculation above because their effect would have been anti-dilutive.