SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue
Total revenues	$ 141,156	$ 134,590	$ 93,589	$ 91,119	$ 87,074	$ 90,385	$ 91,566	$ 85,180	$ 460,454	$ 354,205	$ 344,900
IGS
Disaggregation of Revenue
Total revenues									209,903	183,987	195,155
DHR
Disaggregation of Revenue
Total revenues									85,337	91,059	100,241
Other
Disaggregation of Revenue
Total revenues									84,306	59,995	30,749
Total transaction-based
Disaggregation of Revenue
Total revenues									379,546	335,041	326,145
Development services
Disaggregation of Revenue
Total revenues									31,530	10,285	12,146
Fixed-fee services
Disaggregation of Revenue
Total revenues									49,378	8,879	6,609
State Enterprise
Disaggregation of Revenue
Total revenues									331,720	290,281	312,492
State Enterprise | IGS
Disaggregation of Revenue
Total revenues									209,903	183,987	195,155
State Enterprise | DHR
Disaggregation of Revenue
Total revenues									85,337	91,059	100,241
State Enterprise | Other
Disaggregation of Revenue
Total revenues									0	0	0
State Enterprise | Total transaction-based
Disaggregation of Revenue
Total revenues									295,240	275,046	295,396
State Enterprise | Development services
Disaggregation of Revenue
Total revenues									31,530	10,285	12,146
State Enterprise | Fixed-fee services
Disaggregation of Revenue
Total revenues									4,950	4,950	4,950
Payments
Disaggregation of Revenue
Total revenues									41,092	37,976	10,936
Payments | IGS
Disaggregation of Revenue
Total revenues									0	0	0
Payments | DHR
Disaggregation of Revenue
Total revenues									0	0	0
Payments | Other
Disaggregation of Revenue
Total revenues									41,092	37,976	10,936
Payments | Total transaction-based
Disaggregation of Revenue
Total revenues									41,092	37,976	10,936
Payments | Development services
Disaggregation of Revenue
Total revenues									0	0	0
Payments | Fixed-fee services
Disaggregation of Revenue
Total revenues									0	0	0
TourHealth
Disaggregation of Revenue
Total revenues									61,634	0	0
TourHealth | IGS
Disaggregation of Revenue
Total revenues									0	0	0
TourHealth | DHR
Disaggregation of Revenue
Total revenues									0	0	0
TourHealth | Other
Disaggregation of Revenue
Total revenues									22,415	0	0
TourHealth | Total transaction-based
Disaggregation of Revenue
Total revenues									22,415	0	0
TourHealth | Development services
Disaggregation of Revenue
Total revenues									0	0	0
TourHealth | Fixed-fee services
Disaggregation of Revenue
Total revenues									39,219	0	0
All Other
Disaggregation of Revenue
Total revenues									26,008	25,948	21,472
All Other | IGS
Disaggregation of Revenue
Total revenues									0	0	0
All Other | DHR
Disaggregation of Revenue
Total revenues									0	0	0
All Other | Other
Disaggregation of Revenue
Total revenues									20,799	22,019	19,813
All Other | Total transaction-based
Disaggregation of Revenue
Total revenues									20,799	22,019	19,813
All Other | Development services
Disaggregation of Revenue
Total revenues									0	0	0
All Other | Fixed-fee services
Disaggregation of Revenue
Total revenues									$ 5,209	$ 3,929	$ 1,659