Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Numerator:
Net Income (Loss)	$ 182,033	$ 5,513	$ 198,396	$ 18,360
Denominator:
Weighted-average common shares outstanding, Basic (in shares)	116,444	114,523	115,940	114,080
Effect of potential dilutive common shares	3,098	3,683	3,057	3,460
Denominator:
Weighted-average common shares outstanding, Diluted (in shares)	119,542	118,206	118,997	117,540
Earnings Per Share, Basic	$ 1.56	$ 0.05	$ 1.71	$ 0.16
Earnings Per Share, Diluted	$ 1.52	$ 0.05	$ 1.67	$ 0.16