Note 2 - Acquisitions and Dispositions - Fair Value of Assets Acquired, Liabilities Assumed, and Goodwill from 2016 Acquisitions (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill	$ 611,100	$ 485,318	$ 423,236
KYES-TV Acquisition [Member]
Accounts receivable		0
Other current assets		0
Property and equipment		176
Goodwill		28
Broadcast licenses		254
Other intangible assets		42
Other non-current assets		0
Current liabilities		0
Other long-term liabilities		0
Total		500
WBXX Acquisition [Member]
Accounts receivable		0
Other current assets		429
Property and equipment		1,633
Goodwill		10,288
Broadcast licenses		18,199
Other intangible assets		0
Other non-current assets		408
Current liabilities		(460)
Other long-term liabilities		(497)
Total		30,000
Schurz Acquisition and the Acquisition of WLUC-TV [Member]
Accounts receivable		19,226
Other current assets		4,606
Property and equipment		97,814
Goodwill		61,981
Broadcast licenses		231,391
Other intangible assets		19,523
Other non-current assets		3,028
Current liabilities		(8,903)
Other long-term liabilities		(1,592)
Total		427,074
2016 Acquisitions [Member]
Accounts receivable		19,226
Other current assets		5,035
Property and equipment		99,623
Goodwill		72,297
Broadcast licenses		249,844
Other intangible assets		19,565
Other non-current assets		3,436
Current liabilities		(9,363)
Other long-term liabilities		(2,089)
Total		$ 457,574