- Schedule of Revenue Categories (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue Information
Revenues	$ 87,850	$ 81,819	$ 168,911	$ 157,576
Auto Buying Program revenue
Revenue Information
Revenues	75,271	69,366	147,608	134,520
OEM incentives revenue
Revenue Information
Revenues	7,927	7,837	12,348	13,115
Forecasts, consulting and other revenue
Revenue Information
Revenues	$ 4,652	$ 4,616	$ 8,955	$ 9,941

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Name:	us-gaap_SalesRevenueNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration