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Fair Value Measurement - Narrative (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended		9 Months Ended
	Oct. 31, 2017	Sep. 30, 2017	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of goodwill					$ 332.9
Impairment of equity method investments				$ 5.8	5.8
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of total long-term debt		$ 3,490.0	$ 3,490.0		3,490.0	$ 4,190.0
CareerBuilder
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on sale of CareerBuilder					342.9
Impairment of goodwill					$ 332.9
Hurricane Harvey
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-cash impairment charges for damage to television station and equipment			10.2
Cash expenses related to repairing studio			8.4
Insurance recovery		$ 5.0	11.0
Net expense impact from hurricane			$ 7.6
Subsequent Event \| Hurricane Harvey
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Insurance recovery	$ 6.0