Income tax expense and the effective tax rate for the three months ended March 31, 2018 and 2017 were as follows (in thousands, except the effective tax rate):

The tax provisions for the three months ended March 31, 2018 and 2017 were computed using the estimated effective tax rates applicable to each of the domestic and international taxable jurisdictions for the full year. The Company estimates its effective annual tax rate for 2018 to be between 12% and 17%, which is subject to management’s quarterly review and revision, as necessary.

The Company’s provision for income tax expense and effective income tax rate are significantly impacted by the mix of the Company’s domestic and foreign earnings (loss) before income taxes. In the foreign jurisdictions in which the Company has operations, the applicable statutory rates range from 0% to 34%, which is on average significantly lower than the U.S. federal and state combined statutory rate of approximately 25%.  Due to the enactment of Tax Cuts and Jobs Act (“the Tax Act”) in December 2017, the Company is subject to a tax on global intangible low-taxed income (“GILTI”).  GILTI is a tax on foreign income in excess of a deemed return on tangible assets of foreign corporations. Companies subject to GILTI have the option to account for the GILTI tax as a period cost if and when incurred, or to recognize deferred taxes for temporary differences including outside basis differences expected to reverse as GILTI. The Company has elected to account for GILTI as a period cost, and therefore has included GILTI expense in its effective tax rate calculation for the three months ended March 31, 2018.

The SEC staff issued Staff Accounting Bulletin 118, (“SAB 118”), which provides guidance on accounting for certain tax effects of the Tax Act. SAB 118 provides a measurement period that should not extend beyond one year from the Tax Act enactment date for companies to complete the accounting under Accounting Standards Codification 740 (“ASC 740”). For the three months ended March 31, 2018, the Company obtained additional information which reduced the Company’s provisional accounting for certain tax effects of the Tax Act by $8.0 million, from $99.9 million as reported at December 31, 2017, to $91.9 million at March 31, 2018. Additional work is still necessary to complete a more detailed analysis of the Company's accounting for certain tax effects of the Tax Act. Any subsequent adjustment to certain accounting for the tax effects of the Tax Act will be recorded to current tax expense during the quarter of 2018 when the analysis is completed.

For the three months ended March 31, 2018, the decrease in the Company’s effective tax rate as compared to the three months ended March 31, 2017, was primarily due to an $8.0 million reduction in the Company’s accounting for certain tax effects of the Tax Act, and an increase of $1.1 million in excess tax benefits under ASU 2016-09.

As of March 31, 2018, the Company had approximately $700.1 million in cash and cash equivalents, of which $297.4 million, or 42.5%, was held outside the U.S. Of the $297.4 million held by the Company’s non-U.S. subsidiaries, approximately $124.9 million is available for repatriation to the U.S. without incurring U.S. income taxes and applicable non-U.S. income and withholding taxes in excess of the amounts accrued in the Company’s condensed consolidated financial statements as of March 31, 2018.

The Company’s cash and cash equivalents held in the U.S. and cash provided from operations are sufficient to meet the Company’s liquidity needs in the U.S. for the next twelve months.  However, in anticipation of the needs of the Company’s share repurchase program and the need to provide payment of the Company’s provisional Transition Tax liability, the Company may repatriate certain funds held outside the U.S. for which all applicable U.S. and non-U.S. tax has been fully provided as of March 31, 2018. Because of the need for cash for operating capital and continued overseas expansion, the Company also does not foresee the need for any of its foreign subsidiaries to distribute funds up to an intermediate foreign parent company in any form of taxable dividend. Under current applicable tax laws, if the Company chooses to repatriate some or all of the funds the Company has designated as indefinitely reinvested outside the U.S., the amount repatriated would not be subject to U.S. income taxes but may be subject to applicable non-U.S. income and withholding taxes.