
	Year Ended December 31,
	2020		2019		2018
Current income taxes:
Federal	$	17,150	$	10,343	$	13,704
State	3,561		2,478		2,255
Total	20,711		12,821		15,959
Deferred income taxes:
Federal	(946)		1,182		1,466
State	(537)		500		(18)
Total	(1,483)		1,682		1,448
Total income tax provision	$	19,228	$	14,503	$	17,407

The tax effects of the temporary differences that gave rise to significant components of the Company’s deferred tax assets and liabilities were as follows at December 31 (in thousands):


	2020		2019
Deferred tax assets:
Stock-based compensation	$	1,330	$	983
Federal benefit of state uncertain tax positions	563		746
Accrued vacation	618		521
Deferred rent	112		95
Deferred payroll tax	947		—
State net operating loss carryforwards	53		228
Allowance for doubtful accounts	552		311
Right of use lease liability	2,851		2,840
Other	873		465
Gross deferred tax assets	7,899		6,189
Less: Valuation allowance	(4)		(335)
Total deferred tax assets	7,895		5,854
Deferred tax liabilities:
Property and equipment	(1,830)		(2,027)
Capitalized software development costs	(4,423)		(3,544)
Right of use lease asset	(2,739)		(2,746)
Total deferred tax liabilities	(8,992)		(8,317)
Net deferred tax liability	$	(1,097)	$	(2,463)

Deferred income taxes on the balance sheet result from temporary differences between the amount of assets and liabilities recognized for financial reporting and tax purposes. In assessing the realizability of deferred tax assets, management determines if it is probable the Company will have sufficient taxable income in certain state jurisdictions to fully utilize available tax credits and other components. Deferred tax assets are offset by a valuation allowance to the extent it is more likely than not that they are not expected to be realized. In 2020, the Company identified certain state net operating loss (“NOL”) carryforwards that it had previously identified as unable to use and concluded that it would be able to realize the full amount of these NOL carryforwards. As a result, the Company reduced its deferred tax asset valuation allowance by $0.3 million.


	Year Ended December 31,
	2020		2019		2018
Statutory federal income tax rate	21.0	%	21.0	%	21.0	%
State income taxes	3.5	%	5.0	%	2.3	%

Federal and state tax credits	(2.1)	%	(0.8)	%	(2.3)	%
Tax deficit (benefit) from restricted stock vestings	(0.3)	%	(0.1)	%	0.3	%
Uncertain tax positions (release)	(0.6)	%	(5.2)	%	0.8	%
Nondeductible expenses	0.7	%	2.2	%	0.8	%
Other, net	(0.3)	%	0.2	%	0.1	%
Effective federal and state income tax rate	21.9	%	22.3	%	23.0	%

The Company’s effective tax rate in 2020 was higher than the statutory federal income tax rate due to the effect of state income taxes and nondeductible expenses, partially offset by favorable benefits related to return to the federal research and development credit and other tax adjustments recognized upon filing the Company's 2019 tax return.

The Company’s effective tax rate in 2019 was higher than the statutory federal income tax rate due to the effect of state income taxes and nondeductible expenses, partially offset by the favorable impact of the release of reserves for unrecognized income tax benefits resulting from the expiration of the statutes of limitations for certain tax years and from the completion of an IRS tax examination of the Company’s 2016 consolidated U.S. federal income tax return, which resulted in no changes to the Company’s previously filed return. The effective tax rate was also impacted by approximately $2.6 million of executive severance costs, a significant portion of which was not deductible for income tax purposes.

The Company’s effective tax rate in 2018 was higher than the statutory federal income tax rate due to the effect of state income taxes, uncertain tax positions, and nondeductible expenses, partially offset by favorable benefits related to the federal research and development credit.

The Company recognized $0.4 million in excess tax benefits and $0.1 million and $0.3 million in tax deficits from restricted stock vestings within income tax expense for the years ended December 31, 2020, 2019 and 2018, respectively.

The following table provides a reconciliation of the beginning and ending amount of the consolidated liability for unrecognized income tax benefits (included in other long-term liabilities in the consolidated balance sheets) for the years ended December 31, 2020, 2019 and 2018 (in thousands):


	2020		2019		2018
Balance at January 1	$	5,048	$	8,651	$	8,020
Additions for tax positions of prior years	247		208		459
Additions for tax positions of current years	368		393		1,248
Expiration of the statute of limitations	(1,202)		(3,182)		(1,024)
Reductions for tax positions of prior years	(103)		(217)		(52)
Settlements	—		(805)		—
Balance at December 31	$	4,358	$	5,048	$	8,651

At December 31, 2020 and 2019, there were approximately $3.8 million and $4.3 million, respectively, of unrecognized tax benefits that if recognized would affect the Company’s annual effective tax rate. It is reasonably possible that events will occur during the next 12 months that would cause the total amount of unrecognized tax benefits to increase or decrease. However, the Company does not expect such increases or decreases to be material to its financial condition or results of operations.

The Company, along with its wholly owned subsidiaries, files a consolidated U.S. federal income tax return and separate income tax returns in many states throughout the U.S. The Company remains subject to U.S. federal examination for the tax years ended on or after December 31, 2017. State income tax returns are generally subject to examination for a period of three to five years after filing of the respective return.

The Company recognizes accrued interest and penalties associated with uncertain tax positions as part of income tax expense in the consolidated statements of income. Accrued interest and penalty amounts were not significant at December 31, 2020, 2019 and 2018.