On December 22, 2017, the Tax Cuts and Jobs Act (the “Tax Reform Act”) was signed into law. The legislation significantly changes U.S. tax law by, among other things, lowering corporate income tax rate, implementing a territorial tax system and imposing a repatriation tax on deemed repatriated earnings of foreign subsidiaries. The Tax Reform Act reduces the U.S. corporate income tax rate from a maximum of 35% to a flat 21% rate, effective January 1, 2018. The SEC staff issued Staff Accounting Bulletin No. 118 (“SAB 118”) to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Tax Reform Act. A company may select between one of three scenarios to determine a reasonable estimate arising from the Tax Reform Act. Those scenarios are (i) a final estimate which effectively closes the measurement window; (ii) a reasonable estimate leaving the measurement window open for future revisions; and (iii) no estimate as the law is still being analyzed. The Company made a reasonable estimate for the revaluation of deferred taxes and the effects of the repatriation undistributed foreign subsidiary earnings and profits. As a result of the reduction in the U.S. corporate income tax rate from 35% to 21% under the Tax Reform Act, the Company revalued its net deferred tax liabilities at December 31, 2017, resulting in a $4,683 benefit included in the provision for income taxes for the year ended December 31, 2017. The Tax Reform Act also provided for a one-time deemed mandatory repatriation of Post-1986 E&P through the year ended December 31, 2017. As a result, the Company recognized a provisional $1,250 charge in the provision for income taxes for the year ended December 31, 2017 related to the deemed mandatory repatriation. During 2018, additional work including a more detailed analysis of the Company’s deferred tax assets and liabilities and its historical foreign earnings as well as potential correlative adjustments were completed. In this regard, the Company recorded a one-time $1,089 charge in the provision for income taxes for the year ended December 31, 2018.

	2018			2017		2016
Current:
Federal	$	5,641		$	2,124	$	5,136
State		1,777			1,347		(122	)
Foreign		2,121			570		655
Deferred:
Federal		650			160		(1,345	)
State		(365	)		242		1,216
Foreign		(679	)		—		—
	$	9,145		$	4,443	$	5,540

Total income tax expense differed from the amounts computed by applying the U.S. Federal income tax rate of 21.0% to income before income tax expense as a result of the following:

	2018			2017			2016
Computed tax expense at statutory federal rates	$	7,054		$	8,651		$	6,415
Increase (decrease) in taxes resulting from:
State taxes, net of federal income tax benefit		1,627			988			820
Domestic production deduction		—			(150	)		(1,272	)
Impact of the enactment of the Tax Cuts and Jobs Act (net)		1,089			(3,433	)		—
Income tax credits		(689	)		(431	)		(335	)
Foreign tax rate differential		(37	)		(1,503	)		(1,587	)
Subpart F income		14			3			14
(Gain) loss on equity investments		(61	)		62			123
Stock based compensation		277			262			208
Tax interest		—			(22	)		920
Other		(129	)		16			234
	$	9,145		$	4,443		$	5,540

	2018		2017		2016
Domestic	$	26,124	$	18,931	$	12,513
Foreign		7,472		5,922		6,404
	$	33,596	$	24,853	$	18,917

Temporary differences between the financial statement carrying amounts and tax bases of assets and liabilities that give rise to significant portions of the net deferred tax liability at December 31, 2018 and 2017 relate to the following:

	2018		2017
Deferred tax asset
Inventories	$	3,299	$	3,213
State income taxes		53		330
Program accrual		7,088		7,381
Vacation pay accrual		685		600
Accrued bonuses		1,246		1,073
Bad debt expense		294		12
Stock compensation		1,723		822
NOL carryforward		580		54
Tax credits		779		778
Other		266		381
Deferred tax asset	$	16,013	$	14,644
Deferred tax liability
Plant and equipment, principally due to differences in depreciation and capitalized interest	$	30,269	$	29,986
Prepaid expenses		1,107		942
Deferred tax liability		31,376		30,928
Total net deferred tax liability	$	15,363	$	16,284

The following is a roll-forward of the Company’s total gross unrecognized tax liabilities, not including interest and penalties, for the years ended December 31, 2018 and 2017:

	2018			2017
Balance at beginning of year	$	2,118		$	1,893
Additions for tax positions related to the current year		128			77
Additions for tax positions related to the prior years		24			—
Additions for tax positions related to acquired businesses		—			1,766
Reduction for tax positions related to the prior years		(100	)		(1,618	)
Balance at end of year	$	2,170		$	2,118

The Company recognizes accrued interest and penalties related to unrecognized tax benefits in the provision for income taxes in the Company’s consolidated financial statements. For the years ended December 31, 2018, 2017, and 2016 the Company had recognized approximately $2,368, $2,257, and $408 respectively in interest and penalties related to unrecognized tax benefits.

It is expected that the amount of unrecognized tax benefits will change within the next twelve months; however we do not expect the change to have a significant impact on our consolidated financial statements. At this time, an estimate of the range of the reasonable possible outcomes cannot be made.

The Company believes it is more likely than not that the deferred tax assets detailed in the table above will be realized in the normal course of business. It is the intent of the Company that undistributed earnings of foreign subsidiaries are permanently reinvested. The amount of undistributed earnings was $4,297 as of December 31, 2018. Upon distribution of earnings in the form of dividends or otherwise, the Company may still be subject to state income taxes and withholding taxes payable to the various foreign countries. Determination of the unrecognized deferred tax liability is not practical due to the complexities of a hypothetical calculation.

The Company is subject to U.S. federal income tax as well as to income tax in multiple state jurisdictions. Federal income tax returns of the Company are subject to International Revenue (“IRS”) examination for the 2015 through 2017 tax years. State income tax returns are subject to examination for the 2014 through 2017 tax years. The Company has other foreign income tax returns subject to examination.