Income taxes (Tables)

12 Months Ended

Dec. 31, 2024

Income Tax Disclosure [Abstract]

Schedule of Provision (Benefit) for Income Taxes on Income Consists

The provision (benefit) for income taxes consists of the following (in thousands):

2024	Current		Deferred			Total
Federal	$	154,621	$	120		$	154,741
State and other		23,130		(3,927	)		19,203
Total	$	177,751	$	(3,807	)	$	173,944

2023	Current		Deferred		Total
Federal	$	96,816	$	14,240	$	111,056
State and other		13,646		5,497		19,143
Total	$	110,462	$	19,737	$	130,199

2022	Current		Deferred		Total
Federal	$	161,438	$	13,435	$	174,873
State and other		23,456		4,041		27,497
Total	$	184,894	$	17,476	$	202,370

Schedule of Reconciliation of Effective Tax Rate

The provision for income taxes varies from the U.S. federal statutory tax rate as a result of the following differences:

	2024			2023			2022
U.S. statutory tax rate		21.0	%		21.0	%		21.0	%
Increase (decrease) in taxes resulting from:
State taxes (net of federal income tax benefit)		2.9			2.3			2.7
Purchase of clean energy federal tax credits		(1.0	)		—			—
Uncertain tax positions, settlements and lapse of statutes of limitations		(0.3	)		(0.2	)		—
Valuation allowance on equity method investment		0.1			(0.7	)		0.6
Other valuation allowances, tax rate changes, & deferred adjustments		(0.7	)		0.8			(0.6	)
Non-deductible transaction costs		—			(0.8	)		0.5
Net excess benefits or expense on share-based payments		0.2			(0.1	)		(0.3	)
Non-taxable Merger termination fee		—			(1.3	)		—
Other, net		0.3			0.5			0.4
Effective tax rate		22.5	%		21.5	%		24.3	%

Schedule of Deferred Tax Liabilities and Assets

Deferred tax liabilities and assets were composed of the following as of December 31, 2024 and 2023 (in thousands):

	2024		2023
Deferred tax liabilities
Accelerated amortization of deductible intangibles	$	567,009	$	561,741
Accelerated depreciation		59,558		65,247
Right-of-use assets for operating leases		15,770		18,361
Other		4,097		4,024
Total deferred tax liabilities		646,434		649,373
Deferred tax assets
Accrued compensation costs		23,081		22,450
Pension and post-retirement medical and life		17,804		18,839
Loss carryforwards		15,416		16,435
Operating lease liabilities		16,656		19,443
Other		18,065		18,988
Total deferred tax assets		91,022		96,155
Deferred tax asset valuation allowance		23,801		25,001
Total net deferred tax liabilities	$	579,213	$	578,219

The following table summarizes the activity related to deferred tax asset valuation allowances (in thousands):

	2024			2023			2022
Balance at beginning of year	$	25,001		$	26,339		$	41,929
Additions to valuation allowance		2,212			5,001			7,228
Reductions to valuation allowance		(3,412	)		(6,339	)		(22,818	)
Balance at the end of year	$	23,801		$	25,001		$	26,339

Schedule of Activity Related to Unrecognized Tax Benefits, Excluding Federal Tax Benefit of State Tax Deductions

The following table summarizes the activity related to unrecognized tax benefits, excluding the federal tax benefit of state tax deductions (in thousands):

	2024			2023			2022
Change in unrecognized tax benefits
Balance at beginning of year	$	6,645		$	7,725		$	8,196
Additions based on tax positions related to the current year		123			—			—
Additions for tax positions of prior years		123			151			—
Reductions of tax positions of prior years		(378	)		(680	)		—
Settlements		(1,710	)		—			(9	)
Reductions due to lapse of statutes of limitations		(567	)		(551	)		(462	)
Balance as of end of year	$	4,236		$	6,645		$	7,725