Critical Accounting Estimates Allowance for Doubtful Accounts Income Taxes Long-Lived Assets, Intangibles and Goodwill We have established internal earnings targets that are based on market conditions existing at the time our targets were estab- lished. Based on recent developments, we believe that the current level of activities, workflows, and operating margins within the  North American region will increase slightly over activity experienced during the last quarter of 2013. We believe activity outside of  North America, particularly those relating to oil development projects, will grow moderately into 2014. We expect to meet ongoing working capital needs, capital expenditure requirements and funding of our dividend and share repurchase  programs from a combination of cash on hand, cash flow from operating activities and available borrowings under our Credit Facility. The preparation of financial statements in accordance with U.S. GAAP requires us to make certain estimates and assumptions that  affect the reported amounts of assets and liabilities and disclosure of assets and liabilities at the date of the financial statements  and the reported amounts of revenue and expenses during the reporting period. We evaluate our estimates on an ongoing basis and  determine the adequacy of our estimates based on our historical experience and various other assumptions that we believe are reason- able under the circumstances. By nature, these judgments are subject to an inherent degree of uncertainty. We consider an accounting  estimate to be critical if it is highly subjective and if changes in the estimate under different assumptions would result in a material  impact on our financial condition and results of operations. The following transaction types require significant judgment and, therefore,  are considered critical accounting policies as of December 31, 2013. We evaluate whether client receivables are collectible. We perform ongoing credit evaluations of our clients and monitor collections  and payments in order to maintain a provision for estimated uncollectible accounts based on our historical collection experience and  our current aging of client receivables outstanding in addition to clients’ representations and our understanding of the economic  environment in which our clients operate. Based on our review, we establish or adjust allowances for specific clients and the accounts  receivable as a whole. Our allowance for doubtful accounts at December 31, 2013 was $2.9 million compared to $3.5 million at  December 31, 2012. Our income tax expense includes income taxes of The Netherlands, the U.S. and other foreign countries as well as local, state and  provincial income taxes. We recognize deferred tax assets or liabilities for the differences between the financial statement carrying  amount and tax basis of assets and liabilities using enacted tax rates in effect for the years in which the asset is recovered or the  liability is settled. We estimate the likelihood of the recoverability of our deferred tax assets (particularly, net operating loss  carry-forwards). Any valuation allowance recorded is based on estimates and assumptions of taxable income into the future and  a determination is made of the magnitude of deferred tax assets which are more likely than not to be realized. Valuation allow- ances of our net deferred tax assets aggregated to $6.1 million and $7.2 million at December 31, 2013 and 2012, respectively. If  these estimates and related assumptions change in the future, we may be required to record additional valuation allowances against  our deferred tax assets and our effective tax rate may increase which could result in a material adverse effect on our financial position,  results of operations and cash flows. We have not provided for deferred taxes on the unremitted earnings of certain subsidiaries that  we consider to be permanently reinvested. Should we make a distribution of the unremitted earnings of these subsidiaries, we may be  required to record additional taxes. We record a liability for unrecognized tax benefits resulting from uncertain tax positions taken or  expected to be taken in our tax return. We also recognize interest and penalties, if any, related to unrecognized tax benefits in income  tax expense. Property, plant and equipment are carried at cost less accumulated depreciation. Major renewals and improvements are capitalized while  maintenance and repair costs are charged to expense as incurred. They are depreciated using the straight-line method based on their  individual estimated useful lives, except for leasehold improvements, which are depreciated over the remaining lease term, if shorter.  We estimate the useful lives and salvage values of our assets based on historical data of similar assets. When long-lived assets are sold  or retired, the remaining costs and related accumulated depreciation are removed from the accounts and any resulting gain or loss is  included in income. These capitalized long-lived assets could become impaired if our operating plans or business environment changes. 26