
	2020		2019		2018
Current:
Federal	$	71,123	$	50,145	$	165,303
State	19,597		10,285		26,036
Foreign	71,921		84,433		95,053
Total current	162,641		144,863		286,392
Deferred:
Federal	143		(10,479)		(19,688)
State	(4,323)		3,745		8,727
Foreign	19,848		44,617		8,211
Total deferred	15,668		37,883		(2,750)
Total provision	$	178,309	$	182,746	$	283,642

The provision for income taxes differs from amounts computed by applying the U.S. federal tax rate of 21% for 2020, 2019, and 2018, respectively, to income before income taxes for the years ended December 31, 2020, 2019 and 2018 due to the following (in thousands):


	2020				2019				2018
Computed “expected” tax expense	$	185,330	21.0	%	$	226,342	21.0	%	$	229,976	21.0	%
Changes resulting from:
Change in valuation allowance	25,932		2.9		(28,614)		(2.7)		25,193		2.8
Foreign income tax differential	(20,852)		(2.3)		(15,816)		(1.4)		9,921		0.9
State taxes net of federal benefits	7,489		0.8		12,482		1.2		20,480		1.9
Increase in tax expense due to uncertain tax positions	14,848		1.7		—		—		—		—
Foreign-sourced nontaxable income	—		—		—		—		(28,861)		(2.6)
Foreign withholding tax	15,630		1.8		20,360		1.9		20,569		1.9



Excess tax benefits related to stock-based compensation	(58,942)		(6.7)		(38,156)		(3.5)		(19,255)		(1.8)
Revaluation of capital loss deferred tax asset	—		—		(24,279)		(2.3)		—		—
Impact of the Tax Act:

Foreign tax credit- one-time transition tax	—		—		—		—		17,385		1.6
Deferred tax effects	—		—		—		—		7,128		0.1

Sub-part F Income/GILTI	34,990		4.0		49,859		4.6		40,200		3.7
Foreign tax credits	(30,497)		(3.5)		(38,657)		(3.6)		(52,095)		(4.8)
Other	4,381		0.5		19,225		1.8		13,001		1.2
Provision for income taxes	$	178,309	20.2	%	$	182,746	17.0	%	$	283,642	25.9	%


	2020		2019
Deferred tax assets:
Accounts receivable, principally due to the allowance for doubtful accounts	$	10,515	$	9,586
Accrued expenses not currently deductible for tax	3,442		2,305
Lease deferral	23,506		24,713
Interest rate swap	21,792		13,781
Stock based compensation	36,015		39,779
Income tax credits	51,264		35,845
Net operating loss carry forwards	83,372		67,108
Accrued escheat	3,567		3,098
Other	11,711		3,522
Deferred tax assets before valuation allowance	245,184		199,737
Valuation allowance	(90,340)		(64,482)
Deferred tax assets, net	154,844		135,255
Deferred tax liabilities:
Intangibles—including goodwill	(481,388)		(499,525)
Basis difference in investment in subsidiaries	(42,313)		(42,314)
Lease deferral	(19,977)		(21,810)
Accrued Expense Liability	(513)		(4,023)
Prepaid expenses	(2,126)		(2,075)
Withholding taxes	(30,488)		(30,366)
Property and equipment and other	(71,342)		(52,467)
Deferred tax liabilities	(648,147)		(652,580)
Net deferred tax liabilities	$	(493,303)	$	(517,325)


Balance at December 31, 2017 (after impact of tax reform)	$	59,349
Additions based on changes in deferred tax assets	25,193
Increase in valuation allowance due to rate change from Tax Act	5,824
Balance at December 31, 2018	90,366
Reductions based on changes in deferred tax assets	(28,601)
Additions based on changes in deferred tax assets	2,717
Balance at December 31, 2019	64,482
Additions based on changes in deferred tax assets	25,932
Reductions based on changes in deferred tax assets	(74)
Balance at December 31, 2020	$	90,340

The valuation allowances relate to capital loss carryforwards, income tax credits, foreign net operating loss carryforwards and state net operating loss carryforwards. The net change in the total valuation allowance for the year ended December 31, 2020, was an increase of $25.9 million. The valuation increase from the prior year was primarily due to foreign tax credits generated in Luxembourg due to the payment of various withholding taxes outside of Luxembourg as well as state net operating losses generated in the U.S. in certain states where the Company and its subsidiaries file on a separate company basis.

As of December 31, 2020, the Company had a net operating loss carryforward for U.S. federal income tax purposes of approximately $16.0 million that is available to offset U.S. federal taxable income through 2039. The Company had a net operating loss carryforward for state income tax purposes of approximately $794.2 million that is available to offset future state taxable income through 2039. Additionally, the Company had $114.3 million net operating loss carryforwards for foreign income tax purposes that are available to offset future foreign taxable income. The foreign net operating loss carryforwards will not expire in future years. The Company has provided a valuation allowance against $39.0 million of its deferred tax asset related to the net operating losses as it does not anticipate utilizing the losses in the foreseeable future.

In addition, the Company has foreign tax credits for foreign income purposes in the amount of $51.3 million. The Company has provided a valuation allowance against $51.3 million of the tax credits as it does not anticipate utilizing the credits in the foreseeable future.

During 2020 and 2019, the Company had recorded accrued interest and penalties related to the unrecognized tax benefits of $5.7 million and $3.4 million, respectively. Accumulated interest and penalties were $12.5 million and $12.7 million on the Consolidated Balance Sheets at December 31, 2020 and 2019, respectively. In accordance with the Company's accounting policy, interest and penalties related to unrecognized tax benefits are included as a component of income tax expense.

A reconciliation of the beginning and ending balances of the total amounts of gross unrecognized tax benefits excluding interest and penalties for the years ended December 31, 2020, 2019 and 2018 is as follows (in thousands):


Unrecognized tax benefits at December 31, 2017	$	31,558
Additions based on tax provisions related to the current year	3,755

Deductions based on settlement/expiration of prior year tax positions	(4,161)
Additions based on tax provisions related to the prior year	3,000
Unrecognized tax benefits at December 31, 2018	34,152
Additions based on tax provisions related to the current year	4,284

Additions based on tax provisions related to the prior year	11,679
Deductions based on settlement/expiration of prior year tax positions	(7,342)
Unrecognized tax benefits at December 31, 2019	42,773
Additions based on tax provisions related to the current year	6,412

Additions based on tax provisions related to the prior year	13,532
Deduction of cumulative interest and penalties	(12,508)

Deductions based on expiration of prior year tax positions	(14,460)
Unrecognized tax benefits at December 31, 2020	$	35,749

In prior years, the Company included interest and penalties related to unrecognized tax benefits in its tabular reconciliation above. A cumulative adjustment has been made in 2020 to remove interest and penalties from the above tabular disclosure.

As of December 31, 2020, the Company had total unrecognized tax benefits of $35.7 million all of which, if recognized, would affect its effective tax rate. It is not anticipated that there are any unrecognized tax benefits that will significantly increase or decrease within the next twelve months.

The Company files numerous consolidated and separate income tax returns in the U.S. federal jurisdiction and various state and foreign jurisdictions. The statute of limitations for the Company’s U.S. federal income tax returns has expired for years prior to 2014. The statute of limitations for state income tax returns has expired for years prior to 2014. The statute of limitations for the Company’s U.K. income tax returns has expired for years prior to 2018. The statute of limitations has expired for years prior to 2017 for the Company’s Czech Republic income tax returns, 2017 for the Company’s Russian income tax returns, 2015 for the Company’s Mexican income tax returns, 2015 for the Company’s Brazilian income tax returns, 2015 for the Company’s Luxembourg income tax returns, 2016 for the Company’s New Zealand income tax returns, and 2018 for the Company’s Australian income tax returns.