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, 2017	Mar. 31, 2016
Numerator:
Net income attributable to common stockholders	$ 12,727	$ 13,134
Denominator:
Weighted average shares used to compute net income per share attributable to common stockholders, basic	104,038	101,273
Weighted average effect of potentially dilutive shares to purchase common stock	2,431	2,946
Weighted average shares used to compute net income per share attributable to common stockholders, diluted	106,469	104,219
Net income per share available to common stockholders
Basic	$ 0.12	$ 0.13
Diluted	$ 0.12	$ 0.13