DEFERRED REVENUE AND PERFORMANCE OBLIGATIONS - Deferred Revenue (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Disaggregation of Revenue
Deferred revenue	$ 510,567
Contract With Customer Liability
Balance at beginning of year	461,378
Deferral of revenue	1,177,744
Recognition of deferred revenue	(1,128,555)
Balance at end of year	510,567
Operating segments | Enterprise Software
Disaggregation of Revenue
Deferred revenue	462,010
Contract With Customer Liability
Balance at beginning of year	422,742
Balance at end of year	462,010
Operating segments | Appraisal and Tax
Disaggregation of Revenue
Deferred revenue	35,528
Contract With Customer Liability
Balance at beginning of year	36,945
Balance at end of year	35,528
Operating segments | NIC
Disaggregation of Revenue
Deferred revenue	11,215
Contract With Customer Liability
Balance at beginning of year	0
Balance at end of year	11,215
Corporate
Disaggregation of Revenue
Deferred revenue	1,814
Contract With Customer Liability
Balance at beginning of year	1,691
Balance at end of year	$ 1,814