The income tax provision contains the following components (in thousands):

Income before income taxes relating to non-U.S. operations were $130,000 and $590,000 in the years ended December 31, 2017 and 2016, respectively.

The provision for income taxes differs from the amount of income tax determined by applying the applicable U.S. statutory federal income tax rate to pretax income (loss) as a result of the following differences:

Significant components of the Company's deferred tax assets and liabilities are as follows (in thousands):

The Company has determined through consideration of all positive and negative evidence that the US deferred tax assets are not more likely than not to be realized. The Company recorded a valuation allowance in the US Federal tax jurisdiction for the year ended December 31, 2017. The Tax Cuts and Jobs Act ("TCJA") enacted in December 2017 repealed the corporate AMT for tax years beginning on or after January 1, 2018 and provides for existing AMT tax credit carryovers to be refunded beginning in 2018. The Company has approximately $272,000 in refundable credits, and it expects that a substantial portion will be refunded between 2018 and 2021. As such, the Company does not have a valuation allowance relating to the refundable AMT credit carryforward. A valuation allowance remains on the state and foreign tax attributes that are likely to expire before realization. The valuation allowance increased approximately $3,956,000 for the year ended December 31, 2017 and increased approximately $183,000 for the year ended December 31, 2016.

At December 31, 2017, the Company had approximately $11,914,000 in federal net operating loss carryforwards, which begin to expire in 2029, and approximately $30,752,000 in net operating loss carryforwards from various states. The Company had approximately $1,862,000 in net operating losses in foreign jurisdictions.

Pursuant to Internal Revenue Code ("IRC") Section 382, use of net operating loss and credit carryforwards may be limited if the Company experienced a cumulative change in ownership of greater than 50% in a moving three-year period.  Ownership changes could impact the Company's ability to utilize the net operating loss and credit carryforwards remaining at an ownership change date.  The Company has not completed a Section 382 study.

There was no uncertain tax position related to federal, state and foreign reporting as of December 31, 2017.

U.S. Tax Reform

The TCJA reduces the U.S. federal corporate tax rate from 35% to 21% beginning in 2018, requires companies to pay a one-time transition tax on previously unremitted earnings of non-U.S. subsidiaries that were previously tax deferred, and creates new taxes on certain foreign sourced earnings. The SEC staff issued Staff Accounting Bulletin (SAB) 118, which provides guidance on accounting for enactment effects of the TCJA. SAB 118 provides a measurement period of up to one year from the TCJA’s enactment date for companies to complete their accounting under ASC 740. In accordance with SAB 118, to the extent that a Company’s accounting for certain income tax effects of the TCJA is incomplete but it is able to determine a reasonable estimate, it must record a provisional estimate in its financial statements. If a Company cannot determine a provisional estimate to be included in its financial statements, it should continue to apply ASC 740 on the basis of the provisions of the tax laws that were in effect immediately before the enactment of the TCJA.