The Tax Cuts and Jobs Act (the Act) was enacted on December 22, 2017. The Act reduces the U.S. federal corporate tax rate from 35 percent to 21 percent, allows for immediate deductibility of certain qualified depreciable assets, other changes in the deductibility of items and requires companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred and creates new taxes on certain foreign sourced earnings.

The Company recognized a tax benefit amount of $34 million to reflect the estimated impact of the Act, which is included as a component of income tax expense in 2017. No material changes to this estimate were recognized in 2018. The 2017 tax benefit is the result of remeasuring certain deferred tax assets and liabilities based on the rates at which they are expected to reverse in the future, generally 21 percent.

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. Deferred tax liabilities (assets) are comprised of the following at December 31 (in thousands):

	2018			2017
Depreciation	$	115,775		$	86,506
Other		2,977			93

Gross deferred tax liabilities		118,752			86,599
Allowance for doubtful accounts		(995	)		(988	)
Equity-based compensation		(3,444	)		(2,607	)
Employee benefits		(6,139	)		(5,458	)
Claims and insurance		(17,176	)		(16,929	)
Other		(4,105	)		(1,194	)

Gross deferred tax assets		(31,859	)		(27,176	)

Net deferred tax liability	$	86,893		$	59,423

The Company has determined that a valuation allowance was not necessary at December 31, 2018 or 2017 for substantially all deferred tax assets since it is more likely than not they will be realized from future reversals of temporary differences or future taxable income.

The income tax provision (benefit) for continuing operations consists of the following (in thousands):

	2018		2017			2016
Current:
U.S. federal	$	1,650	$	17,637		$	12,127
State		1,732		1,761			1,988

Total current income tax provision		3,382		19,398			14,115

Deferred:
U.S. federal		27,114		(21,221	)		12,599
State		356		445			181

Total deferred income tax provision		27,470		(20,776	)		12,780

Total income tax provision	$	30,852	$	(1,378	)	$	26,895

A reconciliation between income taxes at the federal statutory rate (21 or 35 percent) and the effective income tax provision is as follows (in thousands):

	2018			2017			2016
Provision at federal statutory rate	$	28,525		$	31,422		$	26,222
State income taxes, net		4,468			2,545			2,418
Tax Cuts and Jobs Act benefit		—			(33,910	)		—
Nondeductible business expenses (benefits)		(49	)		(913	)		462
Tax credits		(1,659	)		(190	)		(1,278	)
Other, net		(433	)		(332	)		(929	)

Total provision	$	30,852		$	(1,378	)	$	26,895

The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction and various state jurisdictions. For the U.S. federal jurisdiction, tax years 2015 - 2018 remain open to examination. The expiration of the statute of limitations related to the various state income tax returns that the Company files varies by state. In general, tax years 2009-2018 remain open to examination by the various state and local jurisdictions. However, a state could challenge certain tax positions back to the 2005 tax year.

A reconciliation of the beginning and ending total amounts of gross unrecognized tax benefits is as follows (in thousands):

	2018			2017
Gross unrecognized tax benefits at beginning of year	$	1,093		$	1,280
Gross decreases in tax positions for prior years		(341	)		(7	)
Gross increases in tax positions for current year		319			171
Settlements		—			—
Lapse of statute of limitations		(202	)		(351	)

Gross unrecognized tax benefits at end of year	$	869		$	1,093

The Company recognizes interest and penalties related to uncertain tax positions as a component of income tax expense. During the years ended December 31, 2018 and 2017, the Company did not record any interest related to unrecognized tax benefits. During the year ended December 31, 2016, the Company recorded interest related to unrecognized tax benefits of approximately $0.1 million. The Company had approximately $0.1 million and $0.1 million of accrued interest and penalties at December 31, 2018 and 2017, respectively. The total amount of unrecognized tax benefits, which is recorded within claims, insurance and other liabilities on the consolidated balance sheets, that would affect the Company’s effective tax rate if recognized is $0.9 million and $1.1 million as of December 31, 2018 and 2017, respectively. The Company paid cash for income taxes of $1.9 million, $17.0 million, and $5.4 million in 2018, 2017 and 2016, respectively.

The Company does not anticipate total unrecognized tax benefits will significantly change during the next twelve months due to the settlements of audits and the expiration of statutes of limitations.

In 2017, the Company recognized a $34 million benefit related to the impact of the Act described above and a $1.7 million benefit related to excess tax benefits from stock activity recognized as a result of the Company’s adoption of ASU 2016-09 effective January 1, 2017.

As a result of legislation enacted in the fourth quarter of 2015, the Company recognized tax credits for alternative fuel usage of approximately $1.0 million in 2016.

In February 2018, US federal tax law changes were enacted that reinstated the tax credits for alternative fuel usage for 2017. The Company recognized the tax credits of approximately $1.0 million in 2018.