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Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount after tax of pro forma income from continuing operations as if the business combination had been completed at the beginning of a period.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition.

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Amount of gain (loss) from sale and disposal of integrated set of activities and assets capable of being conducted and managed for purpose of providing return in form of dividend, lower cost, or other economic benefit to investor, owner, member and participant.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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Note 3 - Acquisitions and Dispositions (Details Textual) - USD ($) $ in Thousands										12 Months Ended
	Aug. 01, 2017	Jun. 01, 2017	May 01, 2017	Jan. 17, 2017	Jan. 13, 2017	Jun. 27, 2016	Jun. 01, 2016	Feb. 16, 2016	Feb. 01, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 30, 2016
Proceeds from Divestiture of Businesses										$ 8,500		$ 11,200
Business Combination, Consideration Transferred, Total												473,074
Goodwill, Ending Balance										612,425	611,100	485,318	$ 485,318
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual											79,800	130,400
Business Acquisition, Pro Forma Income (Loss) from Continuing Operations, Net of Tax											33,700	55,800
Business Combination, Acquisition Related Costs											1,100	7,400
Long-term Debt, Total										2,500,000	1,800,000
Finite-lived Intangible Assets Acquired										0	42,606
Goodwill, Acquired During Period										$ 3,077	125,782	72,300
2016 Term Loan [Member]
Long-term Debt, Total								$ 425,000
Fairbanks Acquistion [Member]
Payments to Acquire Businesses, Gross					$ 8,000
Goodwill, Ending Balance											471
Green Bay Acquisition and Davenport Acquisition [Member]
Business Combination, Consideration Transferred, Total				$ 269,900
Clarksburg Acquisition [Member]
Payments to Acquire Businesses, Gross							$ 16,500
Business Combination, Consideration Transferred, Total			$ 26,500
Goodwill, Ending Balance											3,222
Bangor Acquisition and Gainesville Acquisition [Member]
Business Combination, Consideration Transferred, Total			$ 85,000
Burlington and Plattsburg Acquisition [Member]
Payments to Acquire Businesses, Gross	$ 5,800	$ 23,200
Business Combination, Consideration Transferred, Total	$ 29,000
2017 Acquisitions [Member]
Goodwill, Ending Balance											128,859
2017 Acquisitions [Member] \| Retransmission Agreements [Member]
Finite-Lived Intangible Assets, Gross, Total											$ 27,900
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life											5 years 36 days
2017 Acquisitions [Member] \| Advertising Relationships [Member]
Finite-Lived Intangible Assets, Gross, Total											$ 5,300
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life											10 years 255 days
2017 Acquisitions [Member] \| Income Leases [Member]
Finite-Lived Intangible Assets, Gross, Total											$ 3,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life											11 years 328 days
2017 Acquisitions [Member] \| Minimum [Member]
Property, Plant and Equipment, Useful Life										3 years
2017 Acquisitions [Member] \| Maximum [Member]
Property, Plant and Equipment, Useful Life										40 years
Schurz Acquisition [Member]
Business Combination, Consideration Transferred, Total								443,100
KYES-TV Acquisition [Member]
Payments to Acquire Businesses, Gross						$ 500
Goodwill, Ending Balance												28
WBXX Acquisition [Member]
Proceeds from Divestiture of Businesses												0
Business Combination, Consideration Transferred, Total												30,000
Goodwill, Ending Balance												10,288
Accounts Receivable Contractual Amounts in Excess of Fair Value												$ 200
Schurz Acquisition and Related Transaction [Member] \| Retransmission Agreements [Member]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life												4 years 328 days
Finite-lived Intangible Assets Acquired												$ 14,900
Schurz Acquisition and Related Transaction [Member] \| Advertising Relationships [Member]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life												5 years 182 days
Finite-lived Intangible Assets Acquired												$ 1,600
Schurz Acquisition and Related Transaction [Member] \| Off-Market Favorable Lease [Member]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life												9 years 182 days
Finite-lived Intangible Assets Acquired												$ 2,600
Schurz Acquisition and Related Transaction [Member] \| Minimum [Member]
Property, Plant and Equipment, Useful Life										3 years
Schurz Acquisition and Related Transaction [Member] \| Maximum [Member]
Property, Plant and Equipment, Useful Life										40 years
WSWG-TV [Member]
Proceeds from Divestiture of Businesses										$ 8,500
Gain (Loss) on Disposition of Business										$ 4,800
KAKE-TV [Member]
Proceeds from Divestiture of Businesses									$ 11,200			11,200
Gain (Loss) on Disposition of Business									$ 2,000
Business Combination, Consideration Transferred, Total												$ 0
Schurz Radio Stations [Member]
Proceeds from Divestiture of Businesses								$ 16,000