Acquisitions and Dispositions - Media General - Additional Information (Details)				3 Months Ended								11 Months Ended	12 Months Ended
	Aug. 28, 2017 USD ($)	Jul. 21, 2017 USD ($)	Jan. 17, 2017 USD ($) TelevisionStation Market $ / shares	Dec. 31, 2017 USD ($) Market $ / shares	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) $ / shares	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) Market $ / shares	Dec. 31, 2017 USD ($) Market $ / shares	Dec. 31, 2016 USD ($) $ / shares	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Number of markets in which the Company's stations broadcast | Market				100								100	100
Number of full power television stations whose assets are sold | TelevisionStation			12
Number of markets in which full power television stations are sold | Market			12
Gain (Loss) on sale of business													$ 57,716,000
Initial payments of CVR to holders													263,647,000	$ 2,000,000
Liability to surrender spectrum current				$ 314,087,000								$ 314,087,000	314,087,000
Consolidation of remaining assets in non-controlling interests													7,600,000	108,694,000	$ 2,900,000
Revenue included in consolidated statements of operations and comprehensive income				653,664,000	$ 611,870,000	$ 626,115,000	$ 540,317,000	$ 309,879,000	$ 275,659,000	$ 261,994,000	$ 255,658,000		2,431,966,000	1,103,190,000	896,377,000
Operating income (loss)				140,837,000	$ 129,072,000	$ 138,685,000	$ 110,151,000	$ 92,475,000	$ 72,897,000	$ 64,007,000	$ 57,929,000		518,745,000	$ 287,308,000	$ 206,107,000
Consolidated VIEs [Member]
Business Acquisition [Line Items]
Liability to surrender spectrum current				$ 27,347,000								$ 27,347,000	$ 27,347,000
5.875% Senior Notes Due 2022 [Member]
Business Acquisition [Line Items]
Long-term debt			$ 400,000,000
Interest rate			5.875%
Term Loan A [Member] | Shield Senior Secured Credit Facility [Member]
Business Acquisition [Line Items]
Long-term debt			$ 24,800,000
Network Affiliation Agreements [Member]
Business Acquisition [Line Items]
Network affiliation agreements useful life													15 years	15 years	15 years
Class A Common Stock [Member]
Business Acquisition [Line Items]
Common stock, par value | $ / shares				$ 0.01				$ 0.01				$ 0.01	$ 0.01	$ 0.01
Media General Divestitures [Member]
Business Acquisition [Line Items]
Number of full power television stations whose assets are sold | TelevisionStation			7
Number of markets in which full power television stations are sold | Market			7
Selling price of entities sold			$ 427,600,000
Gain (Loss) on sale of business			$ (4,700,000)
Nexstar Divestitures [Member]
Business Acquisition [Line Items]
Number of full power television stations whose assets are sold | TelevisionStation			5
Selling price of entities sold			$ 114,400,000
Gain (Loss) on sale of business			$ 62,400,000
Media General [Member]
Business Acquisition [Line Items]
Merger effective date			Jan. 17, 2017
Number of full power television stations owned, operated or serviced | TelevisionStation			78
Number of markets in which the Company's stations broadcast | Market			48
Outstanding equity acquired, price per share | $ / shares			$ 10.55
Estimated acquisition date fair value of spectrum asset			$ 465,582,000
Estimated fair value of contingent value rights			271,000,000
Gross proceeds to surrender of spectrum auction		$ 478,600,000
Initial payments of CVR to holders	$ 258,600,000
Taxes paid												$ 180,900,000
Derecognition of spectrum asset to surrender spectrum				$ 34,600,000
Derecognition of spectrum liability to surrender spectrum				34,600,000
Spectrum assets not yet surrendered and retained current				305,800,000								305,800,000	$ 305,800,000
Spectrum assets not yet surrendered and retained noncurrent				126,900,000								126,900,000	126,900,000
Liability to surrender spectrum current				314,100,000								314,100,000	314,100,000
Liability to surrender spectrum noncurrent				$ 130,000,000								130,000,000	130,000,000
Carryover of tax basis in goodwill, deductible for tax purposes			159,000,000
Carryover of tax basis in property and equipment, deductible for tax purposes			247,800,000
Long-term debt			434,269,000
Change in estimated fair value of spectrum asset increased			24,000,000
Decrease in accounts receivable due to changes in estimate of collectability of accounts receivable			23,400,000
Increase in goodwill due to changes in estimate of fair value assumptions			32,800,000
Increase in deferred tax liabilities due to changes in estimate of fair value assumptions			7,400,000
Decrease in income tax payable due to changes in estimate of fair value assumptions			6,500,000
Revenue included in consolidated statements of operations and comprehensive income												1,412,000,000
Operating income (loss)												$ 300,400,000
Acquisition related costs													$ 52,400,000	$ 8,400,000
Media General [Member] | Property and Equipment [Member]
Business Acquisition [Line Items]
Measurement period adjustments, increase (decrease) in acquired intangible assets			(1,800,000)
Media General [Member] | Consolidated VIEs [Member]
Business Acquisition [Line Items]
Consolidation of remaining assets in non-controlling interests			7,600,000
Media General [Member] | FCC licenses [Member]
Business Acquisition [Line Items]
Carryover of tax basis in intangible assets, deductible for tax purposes			294,300,000
Measurement period adjustments, increase (decrease) in acquired intangible assets			$ (255,300,000)
Media General [Member] | Network Affiliation Agreements [Member]
Business Acquisition [Line Items]
Network affiliation agreements useful life			15 years
Carryover of tax basis in intangible assets, deductible for tax purposes			$ 31,700,000
Measurement period adjustments, increase (decrease) in acquired intangible assets			$ 254,500,000
Media General [Member] | Other definite-lived intangible assets [Member]
Business Acquisition [Line Items]
Weighted average estimated useful life of other intangible assets			19 years
Carryover of tax basis in intangible assets, deductible for tax purposes			$ 40,400,000
Measurement period adjustments, increase (decrease) in acquired intangible assets			$ (25,100,000)
Media General [Member] | Class A Common Stock [Member]
Business Acquisition [Line Items]
Percentage of shares issued for each share outstanding			12.49%
Common stock, par value | $ / shares			$ 0.01