STOCK BASED COMPENSATION - Stock Based Compensation Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 1,881	$ 1,117	$ 4,964	$ 4,295
Cost of portal revenues, exclusive of depreciation & amortization
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	365	319	1,166	976
Cost of software & services revenues, exclusive of depreciation & amortization
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	36	22	112	66
Selling & administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 1,480	$ 776	$ 3,686	$ 3,253