Entity information:
7
.
Income Taxes
 
Income tax expense attributable to earnings before income taxes consists of (in thousands):
 
   
Years ended December 31,
  
   
201
7
    
201
6
    
201
5
  
Current:
                        
Federal
   $
134,284
     $
191,422
     $
160,235
  
State and local
    
23,456
      
21,871
      
22,306
  
     
157,740
      
213,293
      
182,541
  
Deferred:
                        
Federal
    
(261,592
)
    
45,846
      
71,292
  
State and local
    
12,828
      
4,568
      
9,135
  
     
(248,764
)
    
50,414
      
80,427
  
Tot
al tax expense/(benefit)
   $
(91,024
)
   $
263,707
     $
262,968
  
 
Income tax expense attributable to earnings before income taxes differed from the amounts computed using the statutory federal income tax rate of
35%
as follows (in thousands):
 
   
Years ended December 31,
  
   
201
7
    
201
6
    
201
5
  
Income tax at federal statutory rate
   $
208,334
     $
243,529
     $
241,571
  
State tax, net of federal effect
    
18,334
      
19,165
      
18,671
  
Federal
tax reform
    
(309,223
)
    
-
      
-
  
Benefit of
stock compensation
   
(4,907
)
    
-
      
-
  
199/R&D
credit
    
(7,056
)
    
-
      
-
  
Nondeductible meals and entertainment
    
1,374
      
1,419
      
1,420
  
Change in effective state tax rate, net of federal benefit
    
3,403
      
(1,055
)
    
1,761
  
Other, net
    
(1,283
)
    
649
      
(455
)
Total tax expense
   $
(91,024
)
   $
263,707
     $
262,968
  
 
The Tax Cuts and Jobs Act (the Act) was enacted
in
December 2017.
Beginning in
2018,
the Act reduces the U.S. federal corporate tax rate from
35%
to
21%.
At
December 31, 2017,
we had
not
completed our accounting for the tax effects of enactment of the Act. However, we have made a reasonable estimate of the effects on our existing deferred tax assets and liabilities based on the rates at which they are expected to reverse in the future, which is generally
21%.
The provisional amount recorded resulting from the remeasurement of our deferred tax balance was
$309.2
million, which is included as a component of income tax from continuing operations. We are still refining our calculations for our
2017
federal income tax return, which will be filed based on the law prior to the Act, and could potentially affect the measurement of these balances. Remaining aspects of the Act are
not
relevant to our operations.
 
Income taxes receivable
was
$61.3
million and
$15.7
million at
December 31, 2017
and
2016,
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, 2017
and
2016,
are presented below (in thousands):
 
   
December 31,
  
   
201
7
    
201
6
  
Deferred tax assets:
                
Insurance accruals
   $
27,700
     $
34,788
  
Allowance for doubtful accounts
    
6,605
      
2,347
  
Compensation accrual
    
3,661
      
10,443
  
Deferred compensation accrual
    
17,620
      
26,062
  
Federal benefit of state uncertain tax positions
    
8,681
      
14,085
  
State NOL carry-forward
    
4,944
      
3,444
  
Other
    
3,134
      
3,853
  
Total gross deferred tax assets
    
72,345
      
95,022
  
Valuation allowance
    
(4,944
)
    
(3,444
 )
Total deferred tax assets, net of valuation allowance
    
67,401
      
91,578
  
Deferred tax liabilities:
                
Plant and equipment, principally due to differences in depreciation
    
566,396
      
831,555
  
Prepaid permits and insurance, principally due to expensing for income tax purposes
    
28,089
      
37,119
  
Other
    
14,786
      
13,538
  
Total gross deferred tax liabilities
    
609,271
      
882,212
  
Net deferred tax liability
   $
541,870
     $
790,634
  
 
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,
  
   
201
7
    
201
6
    
201
5
  
Beginning balance
   $
35.4
     $
32.0
     $
31.6
  
Additions based on tax positions related to the current year
    
11.6
      
10.3
      
9.4
  
Additions/(reductions) based on tax positions taken in prior years
    
5.4
      
(3.2
)
    
(2.5
)
Reductions due to settlements
    
(2.4
)
    
(0.4
)
    
(3.0
)
Reductions due to lapse of applicable statute of limitations
    
(4.7
)
    
(3.3
)
    
(3.5
)
Ending balance
   $
45.3
     $
35.4
     $
32.0
  
 
At
December 31,
201
7
and
2016,
we had a total of
$45.3
million and
$35.4
million, respectively, in gross unrecognized tax benefits.  Of these amounts,
$37.5
million and
$23.0
million represent the amount of unrecognized tax benefits that, if recognized, would impact our effective tax rate in
2017
and
2016,
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, 2017,
2016,
and
2015,
was
$2.1
million,
$1.9
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, 2017
and
2016,
was
$3.6
million and
$4.4
million, respectively.
 
Tax years
201
4
and forward remain subject to examination by federal tax jurisdictions, while tax years
2007
and forward remain open for state jurisdictions.