Significant components of the provision or benefit for income taxes for the years ended December 31 were as follows:

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Components of the deferred tax provision or benefit for the years ended December 31 were as follows:

(1)

The Tax Cuts and Jobs Act, enacted in December 2017, allowed first year bonus depreciation at 100% for assets placed into service between September 27, 2017 and January 1, 2023. Due to a decrease in the purchase of assets eligible for 100% depreciation, the deferred tax expense related to the tax depreciation expense in excess of book depreciation decreased over the two-year period from 2020 through 2021 but increased in 2022.

Significant components of the deferred tax assets and liabilities at December 31 were as follows:


	2022		2021

	(in thousands)
Deferred tax assets:
Accrued expenses	$	53,997	$	47,683
Operating lease right-of-use liabilities		46,056		30,590
Supplemental pension liabilities		81		97
Multiemployer pension fund withdrawal		5,063		5,247
Postretirement liabilities other than pensions		3,137		4,441
Share-based compensation		5,794		6,755
Federal and state net operating loss carryovers		753		1,652
Receivable allowances		3,052		2,778
Other		417		266
Total deferred tax assets		118,350		99,509
Valuation allowance		(1,707)		(2,196)
Total deferred tax assets, net of valuation allowance		116,643		97,313

Deferred tax liabilities:
Amortization, depreciation, and basis differences for property, plant and equipment, and other long-lived assets		117,586		114,999
Operating lease right-of-use assets		44,170		29,403
Intangibles		4,396		6,966
Prepaid expenses		5,424		5,368
Total deferred tax liabilities		171,576		156,736
Net deferred tax liabilities	$	(54,933)	$	(59,423)

Reconciliation between the effective income tax rate, as computed on income before income taxes, and the statutory federal income tax rate for the years ended December 31 is presented in the following table:


	2022			2021			2020

	(in thousands, except percentages)
Income tax provision at the statutory federal rate of 21.0%	$	82,562		$	58,202		$	19,424
Federal income tax effects of:
State income taxes		(4,031)			(2,704)			(1,062)
Nondeductible expenses		5,607			3,596			1,395
Life insurance proceeds and changes in cash surrender value		575			(866)			(488)
Alternative fuel credit		(2,449)			—			(1,261)
Net increase (decrease) in valuation allowances		(464)			887			617
Net increase (decrease) in uncertain tax positions		—			854			(933)
Settlement of share-based compensation		(6,852)			(6,140)			420
Foreign tax credits generated		(849)			(404)			(391)
Federal research and development tax credits		278			(2,044)			(2,078)
Other		524			(1,028)			306
Federal income tax provision		74,901			50,353			15,949
State income tax provision		19,196			12,876			5,056
Foreign income tax provision		849			404			391
Total provision for income taxes	$	94,946		$	63,633		$	21,396
Effective tax rate		24.1	%		23.0	%		23.1	%

Income taxes paid, excluding income tax refunds, totaled $148.7 million, $77.5 million, and $28.6 million in 2022, 2021, and 2020, respectively. Income tax refunds totaled $42.3 million, $19.4 million, and $13.3 million in 2022, 2021, and 2020, respectively.

Under Accounting Standards Codification Topic 718, Compensation – Stock Compensation, the Company may experience volatility in its income tax provision as a result of recording all excess tax benefits and tax deficiencies in the income statement upon settlement of awards, which occurs primarily during the second quarter of each year. The 2022 and 2021 tax rates reflect a tax benefit of 2.1% and 2.8%, respectively, and the 2020 tax rate reflects tax expense of 0.5%, for settlement of stock awards. The tax benefit of dividends on share-based payment awards was less than $0.1 million for each of the years 2022, 2021, and 2020.

At December 31, 2022, the Company had gross federal net operating loss carryforwards of $0.8 million. Due to taxable income, there is no need for a valuation allowance on these amounts at December 31, 2022 or 2021, and the related valuation allowance of $0.1 million was removed at December 31, 2021. At December 31, 2022, the Company had total gross state net operating losses of $9.9 million. Gross state net operating losses of $1.0 million are from the acquisition of Panther and relate to periods ending on or prior to June 15, 2012. State carryforward periods for the remaining Panther net operating losses vary from 10 to 15 years. Gross state net operating losses of $7.3 million are for subsidiaries that have had taxable losses for three or more prior tax years or have other nexus issues that reduce the likelihood of the utilization of the losses. These net operating loss carryforwards have been fully reserved with valuation allowances of $0.4 million and $1.1 million at December 31, 2022 and 2021, respectively. Additional valuation allowances of $0.2 million related to state research and development tax credits were reserved at December 31, 2022 and 2021, and less than $0.1 million related to state interest expense carryforwards was reserved at December 31, 2022 and 2021.

As the Canadian tax rate is now higher than the U.S. tax rate, it is unlikely that foreign tax credit carryforwards will be useable, as U.S. taxes will be paid at a lower rate than the tax rates in Canada. Thus, the foreign tax credit carryover is fully reserved, resulting in valuation allowances of $1.0 million and $0.8 million at December 31, 2022 and 2021, respectively.

Consolidated federal income tax returns filed for tax years through 2018 are closed by the applicable statute of limitations. The Company is not under examination by any federal or foreign taxing authorities at December 31, 2022. The Company is under examination by one state taxing authority at December 31, 2022.

At December 31, 2022 and 2021, there was a reserve for uncertain tax positions of $0.9 million related to credits taken on federal returns.

For 2022, 2021, and 2020, interest paid or accrued related to foreign and state income taxes was immaterial.