Net Income (Loss) per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Numerator:
Net Income (Loss)	$ 17,396	$ (36,860)	$ (144,866)	$ (140,565)
Net income (loss) - diluted	$ 17,396	$ (36,860)	$ (144,866)	$ (140,565)
Denominator:
Weighted average common shares outstanding - basic	65,831	63,555	64,362	63,328
Dilutive effect of stock options	2,632
Weighted-average common shares outstanding and dilutive potential common shares - diluted	68,463	63,555	64,362	63,328
Net income (loss) per share:
Basic (in dollars per share)	$ 0.26	$ (0.58)	$ (2.25)	$ (2.22)
Diluted (in dollars per share)	$ 0.25	$ (0.58)	$ (2.25)	$ (2.22)