Net Loss Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Numerator:
Net loss	$ (151,391)	$ (34,492)	$ (243,569)	$ (83,936)
Denominator:
Average number of common shares outstanding, Basic	65,024,000	62,632,000	63,983,000	62,614,000
Average number of common shares outstanding, diluted	65,024,000	62,632,000	63,983,000	62,614,000
Net loss per share (in dollars per share)	$ (2.33)	$ (0.55)	$ (3.81)	$ (1.34)
Net loss per share (in dollars per share)	$ (2.33)	$ (0.55)	$ (3.81)	$ (1.34)
Effect of dilutive securities (in shares)	0	0	0	0
Anti-dilutive securities excluded from earnings per share calculation	1,886	600	1,348	482
Share-based awards exercised or released
Stock options exercised	8,659		18,300	24,831
Restricted stock units vested	42,849	8,803	78,552	25,676
Total	51,508	8,803	96,852	50,507