INCOME TAX

12 Months Ended

Dec. 31, 2019

The Income tax provision (benefit) on income from operations consists of the following:



	Years Ended December 31,
	2019			2018			2017
Current:
Federal	$	12,814		$	9,110		$	22,883
State	6,585			4,367			4,666
	19,399			13,477			27,549
Deferred	(6,088		)	(5,069		)	(33,664		)
	$	13,311		$	8,408		$	(6,115	)

Reconciliation of the U.S. statutory income tax rate to our effective income tax expense rate for operations follows:



	Years Ended December 31,
	2019			2018			2017
Federal income tax expense at statutory rate	$	33,566		$	32,733		$	57,209
State income tax, net of federal income tax benefit	6,999			7,953			4,754
Domestic production activities deduction	—			—			(2,617		)
Excess tax benefits related to stock option exercises	(29,819		)	(32,487		)	(40,624		)
Tax Act adjustments	—			(1,750		)	(25,992		)
Tax credits	(3,446		)	(3,715		)	(3,578		)
Non-deductible business expenses	6,011			5,655			4,573
Other, net	—			19			160
	$	13,311		$	8,408		$	(6,115	)

The tax effects of the major items recorded as deferred tax assets and liabilities as of December 31 are:



	2019			2018
Deferred income tax assets:
Operating expenses not currently deductible	$	10,214		$	8,989
Stock option and other employee benefit plans	19,308			19,496
Loss and credit carryforwards	23,841			17,999
Total deferred income tax assets	53,363			46,484
Valuation allowance	(1,923		)	(1,049		)
Total deferred income tax assets, net of valuation allowance	51,440			45,435

Deferred income tax liabilities:
Intangible assets	(84,019		)	(70,752		)
Property and equipment	(9,265		)	(8,455		)
Prepaid expenses	(4,922		)	(4,079		)
Deferred revenue	(1,676		)	(3,940		)
Total deferred income tax liabilities	(99,882		)	(87,226		)
Net deferred income tax liabilities	$	(48,442	)	$	(41,791	)

As of December 31, 2019, we had federal net operating loss carryforwards of approximately $85.2 million, after-tax state net operating loss carryforwards of approximately $3.1 million, and tax credit carryforwards of approximately $4.8 million. The federal net operating loss carryforward will begin to expire in 2032 if not utilized, and a portion of the state net operating loss and tax credit carryforwards begin expiring in 2020 if not utilized.

The acquired carryforwards are subject to an annual limitation but are expected to be realized with the exception of certain state net operating loss and tax credit carryforwards. The valuation allowance disclosed in the table above relates to state net operating losses and tax credit carryforwards that are likely to expire before utilization. We believe it is more likely than not that all other deferred tax assets will be realized. However, the amount of the deferred tax asset considered realizable could be adjusted in the future if estimates of reversing taxable temporary differences are revised.

In connection with the acquisition of Socrata in 2018, we recorded a $1.9 million liability for an uncertain tax position associated with acquired tax credit carryforwards. The unrecognized tax benefits are included in deferred income taxes in our consolidated balance sheets. The entire amount, if recognized, would affect the effective tax rate. There was no change in the balance of unrecognized tax benefits during 2019. Based on the information currently available, we do not anticipate a significant increase or decrease to our tax contingencies for these issues for the next 12 months.

We are subject to U.S. federal income tax, as well as income tax of multiple state, local and foreign jurisdictions. We are routinely subject to income tax examinations by these taxing jurisdictions, but we do not have a history of, nor do we expect any material adjustments as a result of these examinations. With few exceptions, major U.S. federal, state, local and foreign jurisdictions are no longer subject to examination for years before 2015. As of February 19, 2020, no significant adjustments have been proposed by any taxing jurisdiction.

We paid income taxes, net of refunds received, of $21.3 million in 2019, $6.8 million in 2018, and $36.0 million in 2017.