Discontinued Operations Gracenote Companies Cash Flows (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Stock-based compensation		$ 5,114	$ 14,963
Capital expenditures		13,673	14,634
Net proceeds from the sale of business (3)		0	551,419
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	1,578	[1],[2]
Net proceeds from the sale of business (3)	[1],[3]		$ 551,419

[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 $581 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.