Income taxes for the years ended December 31, 2021, 2020 and 2019 consisted of the following:

(1)	Current income taxes for the year ended December 31, 2019 include a non-cash income tax benefit of $2.9 million, which relates to discrete adjustments as a result of applying the provisions of the 2017 Tax Cuts and Jobs Act of 2017 (the “Tax Act”).

Income taxes for the years ended December 31, 2021, 2020 and 2019 differ from amounts computed by applying the statutory federal rate to income before income taxes for the following reasons:


	Years Ended December 31,
	2021		2020		2019
Computed federal income tax expense	21.0	%	21.0	%	21.0	%
State income tax	3.1	%	3.5	%	4.1	%
Foreign-derived intangible income (FDII)	(2.5)	%	—	%	—	%
Valuation allowance	(0.3)	%	(0.2)	%	(0.3)	%
Foreign taxes	0.2	%	0.6	%	1.2	%
Remeasurement and discrete adjustments related to the Tax Act (1)	—	%	—	%	(2.7)	%
Share-based payments	(0.2)	%	(0.5)	%	(0.1)	%
Other — net	(0.5)	%	1.0	%	0.1	%
Effective income tax rate	20.8	%	25.4	%	23.3	%

(1)	Effective income tax rate for the year ended December 31, 2019 includes the impact of a non-cash income tax benefit of $2.9 million, or 2.7 percent, which related to certain discrete adjustments as a result of applying the provisions of the Tax Act.

The tax effects of temporary differences that gave rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, 2021 and 2020, were as follows:


	As of December 31,
(In millions)	2021		2020
Deferred tax assets:
Operating lease liabilities	$	111.7	$	63.5
Multi-employer withdrawal liabilities		13.8		15.6
Pension and post-retirement plans		11.1		21.7
Deferred compensation		10.4		8.2
Insurance reserves		6.0		5.3
State net operating losses		5.4		7.5
Other		17.8		15.7
Total deferred tax assets		176.2		137.5
Valuation allowance		(5.3)		(10.0)
Total deferred tax assets, net of valuation allowance		170.9		127.5

Deferred tax liabilities:
Basis differences for property and equipment		423.5		372.4
Operating lease right of use assets		109.3		61.5
Intangibles		41.3		40.5
Investment in SSAT		12.4		7.4
Capital Construction Fund		1.3		6.7
Lease financing		—		22.0
Other		6.0		6.6
Total deferred tax liabilities		593.8		517.1
Deferred tax liability, net	$	422.9	$	389.6

Valuation Allowance: Valuation allowances recorded against the Company’s foreign income tax net operating losses (“NOLs”) and a portion of the state income tax NOLs were $5.3 million and $10.0 million as of December 31, 2021 and 2020, respectively. The Company believes that it is more likely than not that the benefit from these deferred assets will not be realized. The Company recorded a decrease to its valuation allowance of $4.7 million, $0.6 million and $0.9 million during the years ended December 31, 2021, 2020 and 2019, respectively.

Net Operating Losses and Tax Credit Carryforwards: The Company’s NOLs and tax credit carryforwards at December 31, 2021 and 2020 were as follows:


(In millions)	Expiration Date	2021		2020
U.S. Federal income tax NOLs	Various dates beginning in 2027	$	2.4	$	7.6
U.S. State income tax NOLs (1)	Various dates beginning in 2032	$	159.8	$	185.9
U.S. State alternative minimum tax credit	No expiration date	$	4.4	$	4.0
Foreign income tax NOLs	No expiration date	$	8.8	$	11.9

(1)	U.S. State income tax NOLs are presented on a gross tax basis. The Company does not expect to benefit from $157.9 million of U.S. State income tax NOLs as of December 31, 2021 and 2020.

The U.S. federal and state income tax NOLs in the Company’s filed income tax returns include unrecognized tax benefits. The deferred tax assets recognized for those NOLs are presented net of these unrecognized tax benefits. As a result of changes in tax legislation, the use of a portion of the Company’s domestic NOL and tax credit carryforwards may be limited in future periods. Further, a portion of the federal and state income tax NOLs and tax credit carryforwards may expire before being applied to reduce future income tax liabilities.

Unrecognized Tax Benefits: Total unrecognized benefits represent the amount that, if recognized, would favorably affect the Company’s incomes taxes and effective tax rate in future periods. The Company does not expect a material change in gross unrecognized benefits in the next twelve months. A reconciliation of the beginning and ending amount of gross unrecognized tax benefits is as follows:


Unrecognized Tax Benefits (in millions)	Amount
Balance at December 31, 2018	$	15.1
Changes in tax positions of prior years, net		2.1
Reductions for lapse of statute of limitations		(0.8)
Balance at December 31, 2019		16.4
Changes in tax positions of prior years, net		2.1
Reductions for lapse of statute of limitations		(0.2)
Balance at December 31, 2020		18.3
Changes in tax positions of prior years, net		1.1
Reductions for lapse of statute of limitations		(0.2)
Balance at December 31, 2021	$	19.2

Included in the balance of unrecognized tax benefits at December 31, 2021 are potential benefits of $19.2 million that, if recognized, would affect the Company’s income taxes and effective tax rate. The Company recognizes potential accrued interest and penalties related to unrecognized tax benefits in income taxes. To the extent interest and penalties are not ultimately assessed with respect to the settlement of uncertain tax positions, amounts accrued will be reduced and reflected as a reduction of the Company’s income taxes. Interest accrued related to the balance of unrecognized tax benefits totaled $0.1 million as of December 31, 2021 and 2020.

The Company is no longer subject to U.S. federal income tax audits for years before 2015. The Company is routinely involved in federal, state, local income and excise tax audits, and foreign tax audits.