Deferred Revenue and Performance Obligations - Deferred Revenue (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020 USD ($)
Disaggregation of Revenue
Deferred revenue	$ 423,204
Contract With Customer Liability
Beginning balance	412,694
Deferral of revenue	508,126
Recognition of deferred revenue	(497,616)
Ending balance	423,204
Operating segments | Enterprise Software
Disaggregation of Revenue
Deferred revenue	375,838
Contract With Customer Liability
Beginning balance	375,838
Ending balance	396,405
Operating segments | Appraisal and Tax
Disaggregation of Revenue
Deferred revenue	35,487
Contract With Customer Liability
Beginning balance	35,487
Ending balance	25,437
Corporate
Disaggregation of Revenue
Deferred revenue	1,369
Contract With Customer Liability
Beginning balance	1,369
Ending balance	$ 1,362