Note 10 - Goodwill and Intangible Assets (Details Textual) - USD ($) $ in Thousands		12 Months Ended
	Aug. 07, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Amortization of Intangible Assets		$ 25,072	$ 16,596	$ 11,982
Finite-Lived Intangible Assets, Amortization Expense, Year Two		20,600
Finite-Lived Intangible Assets, Amortization Expense, Year Three		15,400
Finite-Lived Intangible Assets, Amortization Expense, Year Four		12,400
Finite-Lived Intangible Assets, Amortization Expense, Year Five		8,300
Finite-Lived Intangible Assets, Amortization Expense, Year Six		4,800
Goodwill, Impairment Loss		0	0	0
Proceeds from Spectrum Auction		$ 90,824	$ 0	$ 0
FCC [Member]
Proceeds from Spectrum Auction	$ 90,800
FCC [Member] | Broadcast Licenses [Member]
Intangible Asset Dispositions from Spectrum Auction	$ (13,100)