Entity information:
Income Taxes

Income taxes for the years ended December 31, 2017, 2016 and 2015 are summarized as follows:
 
December 31,
 
2017
 
2016
 
2015
(in thousands)
 
 
 
 
 
Current:
 
 
 
 
 
Federal tax expense
$
7,289

 
$
7,410

 
$
6,147

State tax expense
2,435

 
2,303

 
372

Deferred:
 
 
 
 
 
Deferred income tax expense
744

 
(2,853
)
 
1,300

Excess tax benefit from share-based award activity
(92
)
 

 

Total income tax provision
$
10,376

 
$
6,860

 
$
7,819



The income tax provision for the year ended December 31, 2017 was more than, and the income tax provision for the years ended December 31, 2016 and 2015 were less than, the amounts computed by applying the maximum effective federal income tax rate of 35% to the income before income taxes for such years because of the following items:
 
2017
 
2016
 
2015
(dollars in thousands)
Amount
 
% of Pretax Income
 
Amount
 
% of Pretax Income
 
Amount
 
% of Pretax Income
Expected provision
$
10,176

 
35.0
 %
 
$
9,538

 
35.0
 %
 
$
11,528

 
35.0
 %
Tax-exempt interest
(3,182
)
 
(10.9
)
 
(3,011
)
 
(11.0
)
 
(2,817
)
 
(8.6
)
Bank-owned life insurance
(485
)
 
(1.7
)
 
(477
)
 
(1.8
)
 
(438
)
 
(1.3
)
State income taxes, net of federal income tax benefit
1,307

 
4.5

 
1,257

 
4.6

 
333

 
1.0

Non-deductible acquisition expenses

 

 
83

 
0.3

 
691

 
2.1

General business credits
(466
)
 
(1.6
)
 
(537
)
 
(2.0
)
 
(1,225
)
 
(3.7
)
Federal income tax rate change
3,212

 
11.1

 

 

 

 

Other
(186
)
 
(0.7
)
 
7

 
0.1

 
(253
)
 
(0.8
)
Total income tax provision
$
10,376

 
35.7
 %
 
$
6,860

 
25.2
 %
 
$
7,819

 
23.7
 %


Net deferred tax assets as of December 31, 2017 and 2016 consisted of the following components:
 
December 31,
 
2017
 
2016
(in thousands)
 
 
 
Deferred income tax assets:
 
 
 
Allowance for loan losses
$
7,311

 
$
8,585

Deferred compensation
1,344

 
1,982

Net operating losses (state net operating loss carryforwards)
4,131

 
3,838

Unrealized losses on investment securities
928

 
738

Other real estate owned
175

 
283

Deferred loan fees
143

 

Other
1,777

 
3,012

Gross deferred tax assets
15,809

 
18,438

 
 
 
 
Deferred income tax liabilities:
 
 
 
Premises and equipment depreciation and amortization
2,604

 
4,092

Federal Home Loan Bank stock
91

 
137

Purchase accounting adjustments
1,179

 
2,352

Mortgage servicing rights
603

 
766

Prepaid expenses
523

 
289

Deferred loan fees

 
225

Other
153

 
216

Gross deferred tax liabilities
5,153

 
8,077

Net deferred income tax asset
10,656

 
10,361

Valuation allowance
4,131

 
3,838

Net deferred tax asset
$
6,525

 
$
6,523


The Tax Act was signed into law on December 22, 2017. The Tax Act has a significant impact on the U.S. corporate income tax regime by lowering the U.S. corporate tax rate from 35 percent to 21 percent effective for taxable years beginning on or after January 1, 2018 in addition to implementing numerous other changes. GAAP requires that the impact of tax legislation be recognized in the period in which the law was enacted.

As a result of the Tax Act, the Company remeasured its deferred tax assets and deferred tax liabilities during the fourth quarter of 2017, resulting in additional income tax expense of $3.2 million.

In December 2017, the SEC staff issued Staff Accounting Bulletin No. 118 (SAB 118), which provides guidance regarding how a company is to reflect provisional amounts when necessary information is not yet available, prepared or analyzed sufficiently to complete its accounting for the effect of the changes in the Tax Act. The income tax expense of $3.2 million recorded during the fourth quarter of 2017 represents all known and estimable impacts of the Tax Act and is a provisional amount based on the Company’s current best estimate. This provisional amount incorporates assumptions made based upon the Company’s current interpretations of the Tax Act and may change as the Company receives additional clarification and implementation guidance, and as data becomes available allowing for a more accurate scheduling of the deferred tax assets and liabilities, including those related to items potentially impacted by the Tax Act such as fixed assets and employee compensation. Adjustments to this provisional amount through December 22, 2018 will be included in income from operations as an adjustment to tax expense in future periods.

The Company has recorded a deferred tax asset for the future tax benefits of Iowa net operating loss carryforwards. The Iowa net operating loss carryforwards amounting to approximately $51.2 million will expire in various amounts from 2018 to 2038. As of December 31, 2017 and 2016, the Company believed it was more likely than not that all temporary differences associated with the Iowa corporate tax return would not be fully realized. Accordingly, the Company has recorded a valuation allowance to reduce the net operating loss carryforward. A valuation allowance related to the remaining deferred tax assets has not been provided because management believes it is more likely than not that the results of future operations will generate sufficient taxable income to realize the deferred tax assets.

The Company had no material unrecognized tax benefits as of December 31, 2017 and 2016.