Earnings Per Share - Computation of Basic and Diluted Net Income per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Numerator:
Net (loss) income attributable to common stockholders	$ (13,862)	$ 28,032
Denominator:
Weighted average shares used to compute net income per share attributable to common stockholders, basic (in shares)	113,912	107,449
Weighted average effect of potentially dilutive shares to purchase common stock (in shares)	0	3,332
Weighted average shares used to compute net income per share attributable to common stockholders, diluted (in shares)	113,912	110,781
Net (loss) income per share attributable to common stockholders
Basic (in dollars per share)	$ (0.12)	$ 0.26
Diluted (in dollars per share)	$ (0.12)	$ 0.25