Acquisitions (Details 11) - Dealix/Autotegrity [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)
Acquired Definite-Lived Intangible Assets
Estimated Fair Value	$ 9,855
Customer Relationships [Member]
Acquired Definite-Lived Intangible Assets
Valuation Method	Excess of earnings	[1]
Estimated Fair Value	$ 7,020
Estimated Useful Life	10 years	[2]
Trademarks and Trade Names Autotegrity [Member]
Acquired Definite-Lived Intangible Assets
Valuation Method	Relief from Royalty	[3]
Estimated Fair Value	$ 120
Estimated Useful Life	3 years	[2]
Trademarks and Trade Names Usedcars.com [Member]
Acquired Definite-Lived Intangible Assets
Valuation Method	Relief from Royalty	[3]
Estimated Fair Value	$ 2,200
Estimated Useful Life	0 years	[2],[4]
Developed Technology [Member]
Acquired Definite-Lived Intangible Assets
Valuation Method	Cost Approach	[5]
Estimated Fair Value	$ 515
Estimated Useful Life	3 years	[2]
Noncompete Agreements CDK [Member]
Acquired Definite-Lived Intangible Assets
Estimated Fair Value	$ 500
Noncompete Agreements Employee [Member]
Acquired Definite-Lived Intangible Assets
Estimated Fair Value	$ 40

[1] The excess of earnings method estimates a purchased intangible asset's value based on the present value of the prospective net cash flows (or excess earnings) attributable to it. The value attributed to these intangibles was based on projected net cash inflows from existing contracts or relationships.

[2] Determination of the estimated useful lives of the individual categories of purchased intangible assets was based on the nature of the applicable intangible asset and the expected future cash flows to be derived from such intangible asset. Amortization of intangible assets with definite lives are recognized over the shorter of the respective lives of the agreement or the period of time the assets are expected to contribute to future cash flows.

[3] The relief from royalty method is an earnings approach which assesses the royalty savings an entity realizes since it owns the asset and isn't required to pay a third party a license fee for its use.

[4] Indefinite

[5] The cost approach estimates the cost required to repurchase or reproduce the intangible assets. The method takes into account technological and economic obsolescence of the technology.