CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues [Abstract]
Total revenues	$ 247,066	$ 221,174
Cost of revenues:
Total cost of revenues	131,018	118,369
Gross profit	116,048	102,805
Selling, general and administrative expenses	57,766	47,604
Research and development expense	18,941	13,048
Amortization of other intangibles	4,850	3,315
Operating income	34,491	38,838
Other income, net	586	599
Income before income taxes	35,077	39,437
Income tax provision	7,729	1,612
Net income	$ 27,348	$ 37,825
Earnings per common share:
Basic (usd per share)	$ 0.71	$ 1.00
Diluted (usd per share)	$ 0.69	$ 0.95
Software licenses and royalties
Revenues [Abstract]
Total revenues	$ 21,793	$ 22,776
Cost of revenues:
Total cost of revenues	818	778
Subscriptions
Revenues [Abstract]
Total revenues	67,275	49,028
Acquired software
Cost of revenues:
Total cost of revenues	6,682	5,382
Software services
Revenues [Abstract]
Total revenues	48,443	45,939
Software services, maintenance and subscriptions
Cost of revenues:
Total cost of revenues	117,160	106,085
Maintenance
Revenues [Abstract]
Total revenues	100,152	93,897
Appraisal services
Revenues [Abstract]
Total revenues	5,214	5,394
Cost of revenues:
Total cost of revenues	3,452	3,781
Hardware and other
Revenues [Abstract]
Total revenues	4,189	4,140
Cost of revenues:
Total cost of revenues	$ 2,906	$ 2,343