REPORTABLE SEGMENTS AND RELATED INFORMATION - Summary of Financial Information for Reportable and Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues:	$ 87,074	$ 90,385	$ 91,566	$ 85,180	$ 78,649	$ 87,028	$ 92,498	$ 86,725	$ 354,205	$ 344,900	$ 336,508
Costs & expenses									279,176	260,723	251,242
Depreciation & amortization	3,535	3,524	3,130	2,421	2,466	2,441	2,145	2,065	12,610	9,117	6,929
Operating income (loss)	$ 11,744	$ 17,971	$ 17,729	$ 14,975	$ 12,569	$ 19,447	$ 22,404	$ 20,640	62,419	75,060	78,337
State Enterprise
Segment Reporting Information [Line Items]
Revenues:									320,700	320,584	311,351
Operating Segments | State Enterprise
Segment Reporting Information [Line Items]
Revenues:									320,700	320,584	311,351
Costs & expenses									203,694	194,989	191,572
Depreciation & amortization									2,724	2,985	2,698
Operating income (loss)									114,282	122,610	117,081
Operating Segments | Software & Services
Segment Reporting Information [Line Items]
Revenues:									33,505	24,316	25,157
Costs & expenses									13,432	9,043	8,890
Depreciation & amortization									1,619	100	97
Operating income (loss)									18,454	15,173	16,170
Other Reconciling Items
Segment Reporting Information [Line Items]
Revenues:									0	0	0
Costs & expenses									62,050	56,691	50,780
Depreciation & amortization									8,267	6,032	4,134
Operating income (loss)									$ (70,317)	$ (62,723)	$ (54,914)