Stock-Based Compensation - Costs Related to Company's Stock-Based Compensation Plan (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expenses	$ 7,726	$ 7,155	$ 12,504	$ 14,111
Cost of revenues
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expenses	1,624	1,638	3,042	2,964
General and administrative expenses
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expenses	3,112	2,781	4,680	5,756
Selling and marketing expenses
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expenses	$ 2,990	$ 2,736	$ 4,782	$ 5,391