REVENUE FROM CONTRACTS WITH CUSTOMERS - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) segment	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Disaggregation of Revenue [Line Items]
Number of reportable segments | segment			2
Net revenues	$ 82,411	$ 69,528	$ 240,290	$ 195,833
Unbilled receivables, current	10,600		10,600		$ 16,000
Contract with customer, liability, revenue recognized			5,900	6,500
Revenue, remaining performance obligation, amount	10,300		10,300
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, amount	$ 4,800		$ 4,800
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 months		12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, amount	$ 1,200		$ 1,200
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year		1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01 | Performance Period Two Through Four
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, amount	$ 5,500		$ 5,500
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, amount	$ 4,100		$ 4,100
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year		1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, amount	$ 200		$ 200
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year		1 year
Data Analytics
Disaggregation of Revenue [Line Items]
Net revenues	$ 2,902	2,372	$ 9,268	7,293
Data Analytics | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Net revenues	$ 1,200	$ 700	$ 4,300	$ 2,500