Discontinued Operations Gracenote Companies Statement of Operations Footnote (Details) - USD ($) $ in Thousands		3 Months Ended
	Feb. 01, 2017	Mar. 31, 2017	Mar. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Repayments of Long-term Debt		$ 584,245	$ 6,960
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		35.00%	35.00%
Gracenote Companies | Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Effective Income Tax Rate Reconciliation, Discontinued Operations, Percent		47.50%	39.20%
Amended Secured Credit Facility | Term B Loans
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Repayments of Long-term Debt	$ 400,000