The tables below show disaggregation of revenue into categories that reflect how economic factors affect the nature, amount, timing, and uncertainty of revenue and cash flows.

Timing of Revenue Recognition

Timing of revenue recognition by revenue category during the period is as follows:



For the three months ended March 31, 2018
	Products and services transferred at a point in time		Products and services transferred over time		Total
Revenues
Software licenses and royalties	$	19,063	$	3,713	$	22,776
Subscriptions	—		49,028		49,028
Software services	—		45,939		45,939
Maintenance	—		93,897		93,897
Appraisal services	—		5,394		5,394
Hardware and other	4,140		—		4,140
Total	$	23,203	$	197,971	$	221,174



For the three months ended March 31, 2017
As Adjusted	Products and services transferred at a point in time		Products and services transferred over time		Total
Revenues
Software licenses and royalties	$	17,115	$	4,643	$	21,758
Subscriptions	—		39,862		39,862
Software services	—		42,496		42,496
Maintenance	—		86,307		86,307
Appraisal services	—		6,612		6,612
Hardware and other	2,694		—		2,694
Total	$	19,809	$	179,920	$	199,729

Recurring Revenue

The majority of our revenue is comprised of recurring revenues from maintenance and subscriptions. Virtually all of our on-premises software clients contract with us for maintenance and support, which provides us with a significant source of recurring revenue. We generally provide maintenance and support for our on-premises clients under annual, or in some cases, multi-year contracts. The contract terms for subscription arrangements range from one to 10 years, but are typically contracted for initial periods of three to five years, providing a significant source of recurring revenues on an annual basis. Non-recurring revenues are derived for all other revenue categories.

Recurring revenues and non-recurring revenues recognized during the period are as follows:



For the three months ended March 31, 2018
	Enterprise Software		Appraisal and Tax		Corporate			Totals

Recurring revenues	$	134,496	$	8,429	$	—		$	142,925
Non-recurring revenues	64,775		13,134		340			78,249
Intercompany	3,237		—		(3,237		)	—
Total revenues	$	202,508	$	21,563	$	(2,897	)	$	221,174



For the three months ended March 31, 2017
As Adjusted	Enterprise Software		Appraisal and Tax		Corporate			Totals

Recurring revenues	$	119,687	$	6,482	$	—		$	126,169
Non-recurring revenues	60,949		12,611		—			73,560
Intercompany	2,163		—		(2,163		)	—
Total revenues	$	182,799	$	19,093	$	(2,163	)	$	199,729