Segment and Related Information - Schedule of Segment Revenues and Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information
Total revenues	$ 271,091	$ 275,124	$ 547,632	$ 522,190
Segment operating income	41,341	36,666	75,234	71,157
Intercompany
Segment Reporting Information
Total revenues	(4,535)	(3,660)	(8,554)	(7,213)
Intercompany | Enterprise Software
Segment Reporting Information
Total revenues	4,533	3,576	8,534	7,060
Intercompany | Appraisal and Tax
Segment Reporting Information
Total revenues	2	84	20	153
Operating segments | Enterprise Software
Segment Reporting Information
Total revenues	247,879	241,055	498,056	462,090
Segment operating income	69,025	59,668	129,497	115,142
Operating segments | Appraisal and Tax
Segment Reporting Information
Total revenues	27,747	31,576	58,128	61,163
Segment operating income	6,148	7,923	13,056	15,018
Corporate
Segment Reporting Information
Total revenues	(4,535)	2,493	(8,552)	(1,063)
Segment operating income	(20,434)	(17,671)	(40,502)	(34,217)
Operating segment and corporate non-segment
Segment Reporting Information
Total revenues				0
Segment operating income	54,739	49,920	102,051	95,943
Software licenses and royalties
Segment Reporting Information
Total revenues	17,025	20,675	35,762	42,468
Software licenses and royalties | Enterprise Software
Segment Reporting Information
Total revenues	14,683	17,555	30,634	36,077
Software licenses and royalties | Appraisal and Tax
Segment Reporting Information
Total revenues	2,342	3,120	5,128	6,391
Software licenses and royalties | Corporate
Segment Reporting Information
Total revenues	0	0	0	0
Subscriptions
Segment Reporting Information
Total revenues	85,638	73,475	167,361	140,750
Subscriptions | Enterprise Software
Segment Reporting Information
Total revenues	79,128	69,386	155,772	132,641
Subscriptions | Appraisal and Tax
Segment Reporting Information
Total revenues	6,510	4,089	11,589	8,109
Subscriptions | Corporate
Segment Reporting Information
Total revenues	0	0	0	0
Software services
Segment Reporting Information
Total revenues	43,654	57,401	95,787	105,844
Software services | Enterprise Software
Segment Reporting Information
Total revenues	38,899	48,404	83,848	88,860
Software services | Appraisal and Tax
Segment Reporting Information
Total revenues	4,755	8,997	11,939	16,984
Software services | Corporate
Segment Reporting Information
Total revenues	0	0	0	0
Maintenance
Segment Reporting Information
Total revenues	116,760	106,689	231,125	206,841
Maintenance | Enterprise Software
Segment Reporting Information
Total revenues	107,336	97,641	212,177	188,829
Maintenance | Appraisal and Tax
Segment Reporting Information
Total revenues	9,424	9,048	18,948	18,012
Maintenance | Corporate
Segment Reporting Information
Total revenues	0	0	0	0
Appraisal services
Segment Reporting Information
Total revenues	4,696	6,233	10,459	11,447
Appraisal services | Enterprise Software
Segment Reporting Information
Total revenues	0	0	0	0
Appraisal services | Appraisal and Tax
Segment Reporting Information
Total revenues	4,696	6,233	10,459	11,447
Appraisal services | Corporate
Segment Reporting Information
Total revenues	0	0	0	0
Hardware and other
Segment Reporting Information
Total revenues	3,318	10,651	7,138	14,840
Hardware and other | Enterprise Software
Segment Reporting Information
Total revenues	3,300	4,493	7,091	8,623
Hardware and other | Appraisal and Tax
Segment Reporting Information
Total revenues	18	5	45	67
Hardware and other | Corporate
Segment Reporting Information
Total revenues	$ 0	$ 6,153	$ 2	$ 6,150