Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Adjusted net income (loss) - diluted numerator	$ 227,363	$ (27,396)	$ 185,061	$ (103,765)
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	10,576	7,501	8,452	7,501
Net Income (Loss) Attributable to Parent	$ 226,086	$ (27,396)	$ 181,271	$ (103,765)
Shares used in computing net income (loss) per common share, Basic	106,272	105,881	106,200	105,800
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	3	0	177	0
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities	10,365	0	10,365	0
Interest expense on Convertible Notes	$ 1,277	$ 0	$ 3,790	$ 0
Adjusted net income (loss)	$ 227,363	$ (27,396)	$ 185,061	$ (103,765)
Shares used in computing net income (loss) per common share, Diluted	116,640	105,881	116,742	105,800
Net income (loss) per common share, Basic	$ 2.13	$ (0.26)	$ 1.71	$ (0.98)
Net income (loss) per common share, Diluted	$ 1.95	$ (0.26)	$ 1.59	$ (0.98)