Summary of Significant Accounting Policies - Disaggregation of Revenues by Major Source (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Total Revenues	$ 92,380	$ 71,296
Subscription
Disaggregation of Revenue [Line Items]
Total Revenues	66,232	50,099
Transactional
Disaggregation of Revenue [Line Items]
Total Revenues	12,820	11,523
Services and Other
Disaggregation of Revenue [Line Items]
Total Revenues	$ 13,328	$ 9,674