Discontinued Operations Gracenote Companies Cash Flows (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Stock-based compensation		$ 6,000	$ 5,000	$ 16,104	$ 27,432
Capital expenditures		22,505	13,324	47,452	41,423
Net proceeds from the sale of business (3)				0	554,487
Gracenote Companies | Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Stock-based compensation				0	1,992	[1]
Capital expenditures		$ 0	$ 0	$ 0	1,578	[1],[2]
Net proceeds from the sale of business (3)	[1],[2],[3]				$ 554,487

[1] (1) Results of operations for the Gracenote Companies are reflected through January 31, 2017, the date of the Gracenote Sale.

[2] (2)Non-cash investing and financing activities of Digital and Data businesses included in the Gracenote Sale were immaterial.

[3] (3)Net proceeds from the sale of business reflects the gross proceeds from the Gracenote sale of $584 million, net of $20 million of the Gracenote Companies’ cash, cash equivalents and restricted cash included in the sale and $9 million of selling costs.