Disaggregation of Revenue

12 Months Ended

Dec. 31, 2018

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue, Deferred Revenue and Performance Obligations, and Deferred Commissions

Disaggregation of Revenue

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 year ended December 31, 2018
	Products and services transferred at a point in time		Products and services transferred over time		Total
Revenues
Software licenses and royalties	$	75,188	$	18,253	$	93,441
Subscriptions	—		220,547		220,547
Software services	—		191,269		191,269
Maintenance	—		384,521		384,521
Appraisal services	—		21,846		21,846
Hardware and other	23,658		—		23,658
Total	$	98,846	$	836,436	$	935,282



For the year ended December 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	$	69,167	$	17,075	$	86,242
Subscriptions	—		172,176		172,176
Software services	—		180,460		180,460
Maintenance	—		359,319		359,319
Appraisal services	—		25,023		25,023
Hardware and other	17,679		—		17,679
Total	$	86,846	$	754,053	$	840,899

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 year ended December 31, 2018
	Enterprise Software		Appraisal and Tax		Corporate			Totals

Recurring revenues	$	570,645	$	34,424	$	—		$	605,069
Non-recurring revenues	269,400		55,932		4,881			330,213
Intercompany	13,155		—		(13,155		)	—
Total revenues	$	853,200	$	90,356	$	(8,274	)	$	935,282



For the year ended December 31, 2017
(As Adjusted)	Enterprise Software		Appraisal and Tax		Corporate			Totals

Recurring revenues	$	502,018	$	29,477	$	—		$	531,495
Non-recurring revenues	252,690		52,102		4,612			309,404
Intercompany	10,425		—		(10,425		)	—
Total revenues	$	765,133	$	81,579	$	(5,813	)	$	840,899

Deferred Revenue and Performance Obligations

Total deferred revenue, including long-term, by segment is as follows:



	December 31, 2018		December 31, 2017
			As Adjusted
Enterprise Software	$	327,521	$	277,198
Appraisal and Tax	20,018		20,387
Corporate	3,397		2,302
Totals	$	350,936	$	299,887

The opening balance of total deferred revenue, including long-term, was $290.1 million (as adjusted) as of January 1, 2017.

Changes in total deferred revenue, including long-term, were as follows:



	2018
Balance at beginning of year (As Adjusted)	$	299,887
Deferral of revenue	871,498
Recognition of deferred revenue	(820,449		)
Balance at end of year	$	350,936

Transaction Price Allocated to the Remaining Performance Obligations

The aggregate amount of transaction price allocated to the remaining performance obligations represents contracted revenue that has not yet been recognized ("Backlog"), which includes deferred revenue and amounts that will be invoiced and recognized as revenue in future periods. Backlog as of December 31, 2018 was $1.25 billion, of which we expect to recognize approximately 50% as revenue over the next 12 months and the remainder thereafter.

Deferred Commissions

Sales commissions earned by our sales force are considered incremental and recoverable costs of obtaining a contract with a customer. Sales commissions for initial contracts are deferred and then amortized commensurate with the recognition of associated revenue over a period of benefit that we have determined to be three to seven years. Deferred commissions were $21.9 million and $19.3 million (as adjusted) as of December 31, 2018, and December 31, 2017, respectively. Amortization expense was $15.6 million for the twelve months ended December 31, 2018 and $11.2 million (as adjusted) for the twelve months ended December 31, 2017, respectively. There were no indicators of impairment in relation to the costs capitalized for the periods presented. Deferred commissions have been included with prepaid expenses in the accompanying consolidated balance sheets. Amortization expense related to deferred commissions is included in selling, general and administrative expenses in the accompanying consolidated statements of income.