Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Net income (loss)	$ (2,897)	$ 47,909	$ 40,667	$ 151,788
Convertible debt income adjustments, net of tax	0	0	0	1,047
Net income (loss) adjusted for convertible debt as used for diluted earnings per share	$ (2,897)	$ 47,909	$ 40,667	$ 152,835
Net income (loss) per share:
Basic (in Dollars per share)	$ (0.02)	$ 0.38	$ 0.33	$ 1.24
Diluted (in Dollars per share)	$ (0.02)	$ 0.38	$ 0.33	$ 1.21
Shares used in computing net income (loss) per share:
Weighted average basic shares outstanding (in Shares)	124,986	125,855	124,691	122,232
Dilutive securities:
Stock option and unvested RSUs (in Shares)	0	479	355	1,137
Shares issuable upon conversion of the notes (in Shares)	0	0	0	2,696
Total dilutive securities (in Shares)		479	355	3,833
Weighted average diluted shares outstanding (in Shares)	124,986	126,334	125,046	126,065
Shares subject to stock options omitted from the calculation of income (loss) per share as their effect would have been anti-dilutive	2,108	3,345	3,264	3,079