Summary of Significant Accounting Policies - Summary of Revenues Disaggregated by Type of Services (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenues	$ 121,116	$ 114,830	$ 303,358	$ 317,628
Promotion
Disaggregation of Revenue [Line Items]
Revenues	62,376	62,034	168,714	183,152
Media
Disaggregation of Revenue [Line Items]
Revenues	$ 58,740	$ 52,796	$ 134,644	$ 134,476