SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 85,180	$ 86,725
IGS
Disaggregation of Revenue [Line Items]
Revenues	50,154	50,267
DHR
Disaggregation of Revenue [Line Items]
Revenues	23,685	27,239
Other
Disaggregation of Revenue [Line Items]
Revenues	7,925	5,934
Total transaction-based
Disaggregation of Revenue [Line Items]
Revenues	81,764	83,440
Development services
Disaggregation of Revenue [Line Items]
Revenues	2,178	2,047
Fixed fee management services
Disaggregation of Revenue [Line Items]
Revenues	1,238	1,238
Software & Services
Disaggregation of Revenue [Line Items]
Revenues	7,925	5,934
Software & Services | IGS
Disaggregation of Revenue [Line Items]
Revenues	0	0
Software & Services | DHR
Disaggregation of Revenue [Line Items]
Revenues	0	0
Software & Services | Other
Disaggregation of Revenue [Line Items]
Revenues	7,925	5,934
Software & Services | Total transaction-based
Disaggregation of Revenue [Line Items]
Revenues	7,925	5,934
Software & Services | Development services
Disaggregation of Revenue [Line Items]
Revenues	0	0
Software & Services | Fixed fee management services
Disaggregation of Revenue [Line Items]
Revenues	0	0
State Enterprise
Disaggregation of Revenue [Line Items]
Revenues	77,255	80,791
State Enterprise | IGS
Disaggregation of Revenue [Line Items]
Revenues	50,154	50,267
State Enterprise | DHR
Disaggregation of Revenue [Line Items]
Revenues	23,685	27,239
State Enterprise | Other
Disaggregation of Revenue [Line Items]
Revenues	0	0
State Enterprise | Total transaction-based
Disaggregation of Revenue [Line Items]
Revenues	73,839	77,506
State Enterprise | Development services
Disaggregation of Revenue [Line Items]
Revenues	2,178	2,047
State Enterprise | Fixed fee management services
Disaggregation of Revenue [Line Items]
Revenues	$ 1,238	$ 1,238