Income taxes	3 Months Ended
Apr. 30, 2018
Income Tax Disclosure [Abstract]
Income taxes [Text Block]	Income taxes The determination of the consolidated provision for income taxes, deferred tax assets and liabilities and related valuation allowances requires management to make judgments and estimates. As a company with subsidiaries in foreign jurisdictions, the process of calculating income taxes involves estimating current tax obligations and exposures in each jurisdiction as well as making judgments regarding the future recoverability of deferred tax assets. Income earned in the United Arab Emirates ("U.A.E.") is not subject to local country income tax. Additionally, the relative proportion of taxable income earned domestically versus internationally can fluctuate significantly from period to period. Changes in the estimated level of annual pre-tax income, tax laws and the results of tax audits can affect the overall effective income tax rate, which impacts the level of income tax expense and net income. Judgments and estimates related to the Company's projections and assumptions are inherently uncertain; therefore, actual results could differ materially from projections. The Company's effective tax rate ("ETR") from operations for the first quarter was 4.1% compared to 12.2% during the respective prior-year periods. The change in the ETR from the prior year-to-date to the current year-to-date was mainly due to tax impact of Canadian business combination which occurred in the prior year. The amount of unrecognized tax benefits, including interest and penalties, at April 30, 2018, recorded in other long-term liabilities was $0.1 million, all of which would impact the Company’s ETR if recognized. The U.S. Tax Cuts and Jobs Act ("Tax Act") was enacted on December 22, 2017 and introduces significant changes to U.S. income tax law. Effective in 2018, the Tax Act reduces the U.S. statutory tax rate from 35% to 21%, effective January 1, and creates new taxes on certain foreign-sourced earnings and certain related-party payments, which are referred to as the global intangible low-taxed income tax and the base erosion anti-abuse tax, respectively. In addition, in 2017 the Company was subject to the onetime transition tax on accumulated foreign subsidiary earnings not previously subject to U.S. income tax. Due to the timing of the enactment and the complexity involved in applying the provisions of the Tax Act, the Company has made reasonable estimates of the effects and recorded provisional amounts in its financial statements as of January 31, 2018 and April 30, 2018. As the Company collects and prepares necessary data, and interprets the Tax Act and any additional guidance issued by the U.S. Treasury Department, the IRS, and other standard-setting bodies, the Company may make future adjustments to the provisional amounts. Furthermore, the Company has considered the impact of the global intangible low-taxed income (GILTI) provision during the quarter and has determined that there is no inclusion based on year-to-date figures. The Company has not elected a method of accounting for GILTI and will continue to monitor the effects of the new provision in future periods.The accounting for the tax effects of the Tax Act will be completed in 2018. Provisional amounts for the following income tax effects of the Tax Act have been recorded as of April 30, 2018 and are subject to change during 2018.

Income taxes

The determination of the consolidated provision for income taxes, deferred tax assets and liabilities and related valuation allowances requires management to make judgments and estimates. As a company with subsidiaries in foreign jurisdictions, the process of calculating income taxes involves estimating current tax obligations and exposures in each jurisdiction as well as making judgments regarding the future recoverability of deferred tax assets. Income earned in the United Arab Emirates ("U.A.E.") is not subject to local country income tax. Additionally, the relative proportion of taxable income earned domestically versus internationally can fluctuate significantly from period to period. Changes in the estimated level of annual pre-tax income, tax laws and the results of tax audits can affect the overall effective income tax rate, which impacts the level of income tax expense and net income. Judgments and estimates related to the Company's projections and assumptions are inherently uncertain; therefore, actual results could differ materially from projections.

The Company's effective tax rate ("ETR") from operations for the first quarter was 4.1% compared to 12.2% during the respective prior-year periods. The change in the ETR from the prior year-to-date to the current year-to-date was mainly due to tax impact of Canadian business combination which occurred in the prior year.

The amount of unrecognized tax benefits, including interest and penalties, at April 30, 2018, recorded in other long-term liabilities was $0.1 million, all of which would impact the Company’s ETR if recognized.

The U.S. Tax Cuts and Jobs Act ("Tax Act") was enacted on December 22, 2017 and introduces significant changes to U.S. income tax law. Effective in 2018, the Tax Act reduces the U.S. statutory tax rate from 35% to 21%, effective January 1, and creates new taxes on certain foreign-sourced earnings and certain related-party payments, which are referred to as the global intangible low-taxed income tax and the base erosion anti-abuse tax, respectively. In addition, in 2017 the Company was subject to the onetime transition tax on accumulated foreign subsidiary earnings not previously subject to U.S. income tax.

Due to the timing of the enactment and the complexity involved in applying the provisions of the Tax Act, the Company has made reasonable estimates of the effects and recorded provisional amounts in its financial statements as of January 31, 2018 and April 30, 2018. As the Company collects and prepares necessary data, and interprets the Tax Act and any additional guidance issued by the U.S. Treasury Department, the IRS, and other standard-setting bodies, the Company may make future adjustments to the provisional amounts. Furthermore, the Company has considered the impact of the global intangible low-taxed income (GILTI) provision during the quarter and has determined that there is no inclusion based on year-to-date figures. The Company has not elected a method of accounting for GILTI and will continue to monitor the effects of the new provision in future periods.The accounting for the tax effects of the Tax Act will be completed in 2018.

Provisional amounts for the following income tax effects of the Tax Act have been recorded as of April 30, 2018 and are subject to change during 2018.