Related Party Transactions (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Related Party Transactions
Prepaid expenses	$ 8,533,000		$ 8,533,000		$ 5,193,000
Other Assets, Current	3,106,000		3,106,000		3,040,000
Receivable from related party	1,988,000		1,988,000		1,865,000
Payable to related party	4,190,000		4,190,000		4,954,000
Dealertrack | Cost of revenue
Related Party Transactions
Costs under related party agreements				$ 400,000
Marketing firm with related officer
Related Party Transactions
Prepaid expenses	1,800,000		1,800,000		900,000
Amounts due to related party	200,000		200,000		0
Marketing firm with related officer | Sales and marketing
Related Party Transactions
Costs under related party agreements	2,800,000	$ 1,300,000	4,100,000	1,600,000
USAA
Related Party Transactions
Receivable from related party	2,000,000		2,000,000		1,900,000
Payable to related party	4,200,000		4,200,000		4,700,000
USAA | Sales and marketing
Related Party Transactions
Costs under related party agreements	3,500,000	$ 3,200,000	6,100,000	6,200,000
Deposits paid to marketing firm
Related Party Transactions
Other Assets, Current	600,000		600,000		$ 0
Amounts paid to marketing firm
Related Party Transactions
Property, Plant and Equipment, Additions	$ 600,000		$ 600,000	$ 0