Other matters - Narrative (Details)				1 Months Ended			3 Months Ended	12 Months Ended
		May 26, 2023 USD ($) Preliminaryapproval	Oct. 03, 2018 Defendant	Jun. 30, 2022 USD ($)	Jun. 30, 2019 Defendant	Dec. 13, 2018 Defendant	Jun. 30, 2023	Dec. 31, 2024 USD ($) Agreement	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Jan. 31, 2022 USD ($)
Business Acquisition [Line Items]
Cost of revenues	[1]							$ 1,756,115,000	$ 1,718,857,000	$ 1,693,221,000
Accounts receivable								$ 604,300,000	624,445,000
Related Party
Business Acquisition [Line Items]
Proceeds from maturity of debt securities available for sale				$ 3,000,000
Related Party | MadHive Inc
Business Acquisition [Line Items]
Related party Transaction, agreement term extension period							2 years
Number of agreements terminated | Agreement								1
Related Party | Intangible Contract Asset
Business Acquisition [Line Items]
Gross											$ 20,800,000
Intangible asset useful life											2 years
Equity And Debt Investment | Related Party
Business Acquisition [Line Items]
Cost of revenues								$ 58,100,000	90,600,000	$ 121,100,000
Accounts receivable								400,000
Accounts payable									$ 5,400,000
Two Customers | Sales Revenue | Customer Concentration Risk
Business Acquisition [Line Items]
Percentage of revenue									10.00%	10.00%
Customer One | Sales Revenue | Customer Concentration Risk
Business Acquisition [Line Items]
Revenues								$ 386,900,000	$ 415,400,000	$ 416,300,000
Customer Two | Sales Revenue | Customer Concentration Risk
Business Acquisition [Line Items]
Revenues									$ 300,500,000	$ 387,300,000
One Customer | Sales Revenue | Customer Concentration Risk
Business Acquisition [Line Items]
Percentage of revenue								10.00%
Clay, Massey & Associates, P.C. v. Gray Television
Business Acquisition [Line Items]
Number of defendants | Defendant			16		4
Loss contingency, number of codefendants | Preliminaryapproval		4
Litigation settlement, amount awarded to other party		$ 0
Loss contingency, damages sought, value		$ 48,000,000
Loss contigency, settlement agreement date, approved by court								Dec. 31, 2023
Settled Litigation
Business Acquisition [Line Items]
Number of defendants | Defendant					4	7

[1] Cost of revenues exclude charges for depreciation and amortization expense, which are shown separately above.