REVENUE

We classify revenue in three categories: service revenue, revenue from reimbursable expenses and non-controlling interests. Service revenue consists of amounts attributable to our fee-based services and sales of short-term investments in real estate. Reimbursable expenses and non-controlling interests are pass-through items for which we earn no margin. Reimbursable expenses consist of amounts we incur on behalf of our customers in performing our fee-based services that we pass directly on to our customers without a markup. Non-controlling interests represent the earnings of Lenders One, a consolidated entity that is a mortgage cooperative managed, but not owned, by Altisource. Lenders One is included in revenue and reduced from net income to arrive at net income attributable to Altisource (see Note 2). Our services are provided to customers located in the United States. The components of revenue were as follows for the years ended December 31:



(in thousands)	2019		2018		2017

Service revenue	$	621,866	$	805,480	$	899,561
Reimbursable expenses	24,172		30,039		39,912
Non-controlling interests	2,613		2,683		2,740

Total	$	648,651	$	838,202	$	942,213

The Company adopted ASU No. 2014-09, Revenue from Contracts from Customers (Topic 606), and related interpretations (“Topic 606”), effective January 1, 2018 retrospectively with the cumulative effect recognized on the date of initial application (the modified retrospective approach) for all contracts. As a result of this adoption, the Company recognized an $11.2 million increase in deferred revenue, a $1.1 million increase in unbilled accounts receivable, a $0.3 million increase in other current liabilities and a $10.4 million decrease in retained earnings as of January 1, 2018. Because the Company adopted Topic 606 retrospectively with a cumulative effect as of January 1, 2018, the comparative results as of and for the year ended December 31, 2017 have not been restated and continue to be reported under ASC Topic 605, Revenue Recognition and SEC Staff Accounting Bulletin Topic 13, Revenue Recognition.

Disaggregation of Revenue

Disaggregation of total revenues by major source is as follows:



(in thousands)	Revenue recognized when services are performed or assets are sold		Revenue related to technology platforms and professional services		Reimbursable expenses revenue		Total revenue

For the year ended December 31, 2019	$	579,929	$	44,550	$	24,172	$	648,651
For the year ended December 31, 2018	719,739		88,424		30,039		838,202

Contract Balances

Our contract assets consist of unbilled accounts receivable (see Note 6). Our contract liabilities consist of current deferred revenue as reported on the accompanying consolidated balance sheets and non-current deferred revenue (see Note 15). Revenue recognized that was included in the contract liability at the beginning of the period, including amounts added to the contract liability as part of the cumulative effect of adopting Topic 606 was $9.8 million and $20.6 million for the years ended December 31, 2019 and 2018, respectively.