7.	Income Taxes

Income tax expense attributable to earnings before income taxes consists of (in thousands):

	Years ended December 31,
	2018		2017			2016
Current:
Federal	$	22,904	$	134,284		$	191,422
State and local		26,738		23,456			21,871
		49,642		157,740			213,293
Deferred:
Federal		97,670		(261,592	)		45,846
State and local		3,921		12,828			4,568
		101,591		(248,764	)		50,414
Total tax expense/(benefit)	$	151,233	$	(91,024	)	$	263,707

Income tax expense attributable to earnings before income taxes differed from the amounts computed using the statutory federal income tax rate of

21%

as follows (in thousands):

	Years ended December 31,
	2018			2017			2016
Income tax at federal statutory rate	$	134,572		$	208,334		$	243,529
State tax, net of federal effect		24,627			18,334			19,165
Federal tax reform		(3,219	)		(309,223	)		-
Benefit of stock compensation		(4,919	)		(4,907	)		-
199/R&D credit		1,000			(7,056	)		-
Nondeductible meals and entertainment		1,071			1,374			1,419
Change in effective state tax rate, net of federal benefit		(1,469	)		3,403			(1,055	)
Other, net		(430	)		(1,283	)		649
Total tax expense	$	151,233		$	(91,024	)	$	263,707

The Tax Cuts and Jobs Act (the Act) was enacted in

December 2017.

Beginning in

2018,

the Act reduced the U.S. federal corporate tax rate from

35%

21%.

December 31, 2017,

we had

not

completed our accounting for the tax effects of enactment of the Act. However, we made a reasonable estimate of the effects on our existing deferred tax assets and liabilities based on the rates at which they were expected to reverse in the future, which was generally

21%.

The provisional amount recorded resulting from the remeasurement of our deferred tax balance was

$309.2

million, which was included as a component of

2017

income tax from continuing operations. During

2018,

we finalized our calculations for our

2017

federal income tax return, which was filed based on the law prior to the Act, resulting in

significant change to the initial measurement of these balances. Remaining aspects of the Act were

not

relevant to our operations.

Income taxes receivable was

$102.4

million and

$61.3

million at

December 31, 2018

and

2017,

respectively. These amounts have been included in other receivables in our Consolidated Balance Sheets. The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at

December 31, 2018

and

2017,

are presented below (in thousands):

	December 31,
	2018			2017
Deferred tax assets:
Insurance accruals	$	34,889		$	27,700
Allowance for doubtful accounts		7,649			6,605
Compensation accrual		10,461			3,661
Deferred compensation accrual		20,396			17,620
Federal benefit of state uncertain tax positions		10,364			8,681
State NOL carry-forward		6,041			4,944
Other		4,626			3,134
Total gross deferred tax assets		94,426			72,345
Valuation allowance		(6,041	)		(4,944	)
Total deferred tax assets, net of valuation allowance		88,385			67,401
Deferred tax liabilities:
Plant and equipment, principally due to differences in depreciation		696,913			566,396
Prepaid permits and insurance, principally due to expensing for income tax purposes		33,594			28,089
Other		1,339			14,786
Total gross deferred tax liabilities		731,846			609,271
Net deferred tax liability	$	643,461		$	541,870

Guidance on accounting for uncertainty in income taxes prescribes recognition and measurement criteria and requires that we assess whether the benefits of our tax positions taken are more likely than

not

of being sustained under tax audits. We have made adjustments to the balance of unrecognized tax benefits, a component of other long-term liabilities on our Consolidated Balance Sheets, as follows (in millions):

	December 31,
	2018			2017			2016
Beginning balance	$	45.3		$	35.4		$	32.0
Additions based on tax positions related to the current year		13.9			11.6			10.3
Additions/(reductions) based on tax positions taken in prior years		(2.4	)		5.4			(3.2	)
Reductions due to settlements		-			(2.4	)		(0.4	)
Reductions due to lapse of applicable statute of limitations		(4.6	)		(4.7	)		(3.3	)
Ending balance	$	52.2		$	45.3		$	35.4

December 31, 2018

and

2017,

we had a total of

$52.2

million and

$45.3

million, respectively, in gross unrecognized tax benefits. Of these amounts,

$43.1

million and

$37.5

million represent the amount of unrecognized tax benefits that, if recognized, would impact our effective tax rate in

2018

and

2017,

respectively. Interest and penalties related to income taxes are classified as interest expense in our Consolidated Statements of Earnings. The amount of accrued interest and penalties recognized during the years ended

December 31, 2018,

2017,

and

2016,

was

$2.4

million,

$2.1

million, and

$1.9

million, respectively. Future changes to unrecognized tax benefits will be recognized as income tax expense and interest expense, as appropriate. The total amount of accrued interest and penalties for such unrecognized tax benefits at

December 31, 2018

and

2017,

was

$4.6

million and

$3.6

million, respectively.

Tax years

2015

and forward remain subject to examination by federal tax jurisdictions, while tax years

2008

and forward remain open for state jurisdictions.