Investments Marketable Equity Securities (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
	Jan. 31, 2017	Mar. 31, 2017	Sep. 30, 2018	Sep. 30, 2017	Aug. 04, 2014
Schedule of Equity Method Investments [Line Items]
Gain on investment transaction			$ (1,113)	$ 10,617
Tribune Publishing
Schedule of Equity Method Investments [Line Items]
Tribune Publishing common stock retained, shares					381,354
Ownership percentage in common stock					1.50%
Proceeds from the sale of investment	$ 5,000
Gain on investment transaction		$ 5,000