STOCK-BASED COMPENSATION AND EMPLOYEE BENEFIT PLANS - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 5,464	$ 5,997	$ 6,441
Cost of portal revenues, exclusive of depreciation & amortization
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,276	1,390	1,404
Cost of software & services revenues, exclusive of depreciation & amortization
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	86	62	83
Selling & administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 4,102	$ 4,545	$ 4,954