Retirement plans - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Nov. 30, 2023	Dec. 31, 2022
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
401(k) employee maximum matching contribution (up to)	50.00%
401(k) employer matching contribution	100.00%
Contributions per employee subject to employer match	4.00%
Compensation expense related to 401(k) contributions	$ 18,700,000	$ 18,600,000		$ 18,700,000
Expenses incurred for multi-employer withdrawal liabilities	$ 0	0		0
AFTRA Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded percentage	88.00%
Contribution by employer	$ 2,900,000	2,800,000		$ 2,700,000
AFTRA Plan | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
CBA contribution as a percent of total contribution			5.00%
Retirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial (loss) gain	$ 14,400,000	$ (9,443,000)
Discount rate	5.60%	5.20%		5.50%
Discount rate	5.20%	5.50%		2.89%
Actuarial gain (losses) from change in discount rate	$ 13,000,000	$ 10,900,000
Cash contributions	$ 7,524,000	$ 3,833,000
Actual rate of return on plan assets (as a percent)	2.40%	10.00%		(23.00%)
Retirement Plans | Corporate stock
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target allocation	14.00%
Retirement Plans | Debt securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target allocation	86.00%
TRP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Cash contributions	$ 3,700,000	$ 0
Contributions expected to be made during next fiscal year	0
SERP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Cash contributions	3,700,000	$ 3,800,000
Contributions expected to be made during next fiscal year	$ 5,900,000