Other matters (Details)				1 Months Ended			3 Months Ended		15 Months Ended	23 Months Ended
	Mar. 02, 2020 USD ($) market	Jun. 17, 2019 defendant	Jul. 30, 2018 defendant	Jun. 30, 2019 defendant	Dec. 13, 2018 defendant	Apr. 30, 2017 USD ($) phase station	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Mar. 23, 2018 USD ($)
Business Acquisition [Line Items]
Number of stations assigned new channels | station						17
Broadcast Spectrum Program, Number of Stations Acquired | station						4
Authorized reimbursement amount						$ 1,750,000,000
Authorized reimbursement amount, repacking fund												$ 1,000,000,000
Authorized reimbursement amount, repacking fund, full power, class a stations and multichannel distributors												$ 750,000,000
Repacking period						39 months
Number of repacking phases | phase						10
Broadcast Spectrum Program, Number of Repacking Phases, Phase Two | phase						2
Broadcast Spectrum Program, Number of Repacking Phases, Phase Nine | phase						10
Capital expenditures incurred									$ 38,500,000
Broadcast Spectrum Program, Amount Purchased							$ 2,900,000
FCC reimbursements received										$ 31,900,000
Payments for acquisition of minority interest	$ 14,000,000.0						14,000,000	$ 0
Settled litigation
Business Acquisition [Line Items]
Number of other broadcasters settling DOJ complaint (defendant) | defendant		4			7
Equity And Debt Investment | Affiliated Entity
Business Acquisition [Line Items]
Expenses incurred with related party							10,500,000	$ 6,500,000
Accounts payable and accrued liabilities with related party							$ 7,500,000		$ 7,500,000	$ 7,500,000	$ 4,300,000
Clay, Massey & Associates, P.C. v. Gray Television
Business Acquisition [Line Items]
Number of other broadcasters settling DOJ complaint (defendant) | defendant			16	4
Gray Television
Business Acquisition [Line Items]
Number of television markets | market	93