Segment and Related Information - Schedule of Segment Revenues and Operations (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information
Total Revenue	$ 276,541	$ 247,066
Operating income	33,893	34,491
Operating segments | Enterprise Software
Segment Reporting Information
Total Revenue	250,177	221,035
Operating income	60,472	55,474
Operating segments | Appraisal and Tax
Segment Reporting Information
Total Revenue	30,381	29,587
Operating income	6,908	7,095
Intercompany
Segment Reporting Information
Total Revenue	(4,019)	(3,553)
Intercompany | Enterprise Software
Segment Reporting Information
Total Revenue	4,001	3,484
Intercompany | Appraisal and Tax
Segment Reporting Information
Total Revenue	18	69
Corporate
Segment Reporting Information
Total Revenue	(4,017)	(3,556)
Operating income	(20,068)	(16,546)
Operating segment and corporate non-segment
Segment Reporting Information
Operating income	47,312	46,023
Software licenses and royalties
Segment Reporting Information
Total Revenue	18,737	21,793
Software licenses and royalties | Enterprise Software
Segment Reporting Information
Total Revenue	15,951	18,522
Software licenses and royalties | Appraisal and Tax
Segment Reporting Information
Total Revenue	2,786	3,271
Software licenses and royalties | Corporate
Segment Reporting Information
Total Revenue	0	0
Subscriptions
Segment Reporting Information
Total Revenue	81,723	67,275
Subscriptions | Enterprise Software
Segment Reporting Information
Total Revenue	76,644	63,255
Subscriptions | Appraisal and Tax
Segment Reporting Information
Total Revenue	5,079	4,020
Subscriptions | Corporate
Segment Reporting Information
Total Revenue	0	0
Software services
Segment Reporting Information
Total Revenue	52,133	48,443
Software services | Enterprise Software
Segment Reporting Information
Total Revenue	44,949	40,456
Software services | Appraisal and Tax
Segment Reporting Information
Total Revenue	7,184	7,987
Software services | Corporate
Segment Reporting Information
Total Revenue	0	0
Maintenance
Segment Reporting Information
Total Revenue	114,365	100,152
Maintenance | Enterprise Software
Segment Reporting Information
Total Revenue	104,841	91,188
Maintenance | Appraisal and Tax
Segment Reporting Information
Total Revenue	9,524	8,964
Maintenance | Corporate
Segment Reporting Information
Total Revenue	0	0
Appraisal services
Segment Reporting Information
Total Revenue	5,763	5,214
Appraisal services | Enterprise Software
Segment Reporting Information
Total Revenue	0	0
Appraisal services | Appraisal and Tax
Segment Reporting Information
Total Revenue	5,763	5,214
Appraisal services | Corporate
Segment Reporting Information
Total Revenue	0	0
Hardware and other
Segment Reporting Information
Total Revenue	3,820	4,189
Hardware and other | Enterprise Software
Segment Reporting Information
Total Revenue	3,791	4,130
Hardware and other | Appraisal and Tax
Segment Reporting Information
Total Revenue	27	62
Hardware and other | Corporate
Segment Reporting Information
Total Revenue	$ 2	$ (3)